diff --git a/.travis.yml b/.travis.yml
index ef045a9..02e0d82 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,12 +4,14 @@ cache: pip
 
 python:
   - 3.6
+  - 3.7
+  - 3.8
 env:
   global:
     - BUILD_ENVIRONMENT=development
 
 install: make dev-install
-script: make dev-test-single
+script: make dev-test-full
 after_success: make dev-cov
 
 notifications:
diff --git a/docker-compose.yml b/docker-compose.yml
index c91a45a..3058584 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -1,9 +1,13 @@
 version: "3"
 
 services:
-    auditorium:
-        image: docker.pkg.github.com/apiad/auditorium/auditorium:latest
-        build: "."
-        volumes:
-            - "./:/code"
-        command: make test
+  auditorium-tester:
+    container_name: auditorium-tester-${PYTHON_VERSION}
+    image: docker.pkg.github.com/apiad/auditorium/auditorium:${PYTHON_VERSION}
+    build:
+      context: "."
+      args:
+        PYTHON_VERSION: ${PYTHON_VERSION}
+    volumes:
+      - "./:/code"
+    command: make dev-test-full
diff --git a/dockerfile b/dockerfile
index 730a47b..08afab5 100644
--- a/dockerfile
+++ b/dockerfile
@@ -1,14 +1,27 @@
-FROM python:3.6
+# =====================
+# Generic build system
+# ---------------------
+
+ARG PYTHON_VERSION
+
+FROM python:${PYTHON_VERSION}
+
+RUN echo Building image for Python:${PYTHON_VERSION}
+
+# ==========================================
+# Project-specific installation instruction
+# ------------------------------------------
 
 WORKDIR /code
 COPY pyproject.toml poetry.lock makefile /code/
 
 ENV BUILD_ENVIRONMENT="development"
-ENV XDG_CACHE_HOME="/opt/venv/cache"
+ENV XDG_CACHE_HOME="/opt/dev/cache"
 
+# Use system's Python for installing dev tools
 RUN make dev-install
 
 COPY . /code
 
-VOLUME [ "/opt/venv" ]
-CMD bash
+VOLUME [ "/opt/dev" ]
+CMD [ "bash" ]
diff --git a/makefile b/makefile
index 79de5df..ded4edd 100644
--- a/makefile
+++ b/makefile
@@ -1,24 +1,36 @@
-.PHONY: clean lint test test-full
+.PHONY: clean lint test-fast test-full shell
+
+BASE_VERSION := 3.8
+ALL_VERSIONS := 3.6 3.7 3.8
+
+test-fast:
+	PYTHON_VERSION=${BASE_VERSION} docker-compose run auditorium-tester make dev-test-fast
+
+shell:
+	PYTHON_VERSION=${BASE_VERSION} docker-compose run auditorium-tester bash
 
 build:
-	docker-compose run auditorium make dev-build
+	PYTHON_VERSION=${BASE_VERSION} docker-compose run auditorium-tester make dev-build
 
 clean:
 	git clean -fxd
 
 lint:
-	docker-compose run auditorium poetry run pylint auditorium
-
-test:
-	docker-compose run auditorium make dev-test-simple
+	PYTHON_VERSION=${BASE_VERSION} docker-compose run auditorium-tester poetry run pylint auditorium
 
 test-full:
-	docker-compose run auditorium make dev-test-full
+	$(foreach VERSION, $(ALL_VERSIONS), PYTHON_VERSION=${VERSION} docker-compose up;)
+
+docker-build:
+	$(foreach VERSION, $(ALL_VERSIONS), PYTHON_VERSION=${VERSION} docker-compose build;)
+
+docker-push:
+	$(foreach VERSION, $(ALL_VERSIONS), PYTHON_VERSION=${VERSION} docker-compose push;)
 
 # Below are the commands that will be run INSIDE the development environment, i.e., inside Docker or Travis
 # These commands are NOT supposed to be run by the developer directly, and will fail to do so.
 
-.PHONY: dev-build clean dev-install dev-test dev-cov dev-ensure
+.PHONY: dev-ensure dev-build dev-install dev-test-fast dev-test-full dev-cov
 
 dev-ensure:
 	# Check if you are inside a development environment
@@ -28,23 +40,18 @@ dev-build: dev-ensure
 	poetry build
 
 dev-install: dev-ensure
-	pip install -U pip
 	pip install poetry
-	pip install tox
 	poetry config virtualenvs.create false
 	poetry install
 
-dev-test-full: dev-ensure
-	tox
-
-dev-test-simple: dev-ensure
-	poetry run mypy -p auditorium --ignore-missing-imports
-	poetry run pytest --doctest-modules --cov=auditorium --cov-report=term-missing -v
+dev-test-fast: dev-ensure
+	python -m mypy -p auditorium --ignore-missing-imports
+	python -m pytest --doctest-modules --cov=auditorium --cov-report=term-missing -v
 
-dev-test-single: dev-ensure
-	poetry run auditorium test
-	poetry run mypy -p auditorium --ignore-missing-imports
-	poetry run pytest --doctest-modules --cov=auditorium --cov-report=xml
+dev-test-full: dev-ensure
+	python -m auditorium test
+	python -m mypy -p auditorium --ignore-missing-imports
+	python -m pytest --doctest-modules --cov=auditorium --cov-report=xml
 
 dev-cov: dev-ensure
-	poetry run codecov
+	python -m codecov
diff --git a/poetry.lock b/poetry.lock
index bc3a401..7423462 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -295,7 +295,7 @@ description = "multidict implementation"
 name = "multidict"
 optional = false
 python-versions = ">=3.5"
-version = "4.7.1"
+version = "4.7.2"
 
 [[package]]
 category = "dev"
@@ -614,8 +614,8 @@ docs = ["sphinx", "jaraco.packaging (>=3.2)", "rst.linker (>=1.9)"]
 testing = ["pathlib2", "contextlib2", "unittest2"]
 
 [metadata]
-content-hash = "0bf20f273ad5ab11feca26e3666362255d4fbf735db90c15f7c739ef05205720"
-python-versions = "~3.6"
+content-hash = "31994f3e5d3c8f3f7e6ed0b3922cfa47e8a3d48ac610f0e96a7683b5653cd618"
+python-versions = "^3.6"
 
 [metadata.files]
 aiofiles = [
@@ -844,23 +844,23 @@ more-itertools = [
     {file = "more_itertools-8.0.2-py3-none-any.whl", hash = "sha256:c833ef592a0324bcc6a60e48440da07645063c453880c9477ceb22490aec1564"},
 ]
 multidict = [
-    {file = "multidict-4.7.1-cp35-cp35m-macosx_10_13_x86_64.whl", hash = "sha256:258660e9d6b52de1a75097944e12718d3aa59adc611b703361e3577d69167aaf"},
-    {file = "multidict-4.7.1-cp35-cp35m-manylinux1_x86_64.whl", hash = "sha256:c42362750a51a15dc905cb891658f822ee5021bfbea898c03aa1ed833e2248a5"},
-    {file = "multidict-4.7.1-cp35-cp35m-win32.whl", hash = "sha256:09c19f642e055550c9319d5123221b7e07fc79bda58122aa93910e52f2ab2f29"},
-    {file = "multidict-4.7.1-cp35-cp35m-win_amd64.whl", hash = "sha256:ec804fc5f68695d91c24d716020278fcffd50890492690a7e1fef2e741f7172c"},
-    {file = "multidict-4.7.1-cp36-cp36m-macosx_10_13_x86_64.whl", hash = "sha256:725496dde5730f4ad0a627e1a58e2620c1bde0ad1c8080aae15d583eb23344ce"},
-    {file = "multidict-4.7.1-cp36-cp36m-manylinux1_x86_64.whl", hash = "sha256:e53b205f8afd76fc6c942ef39e8ee7c519c775d336291d32874082a87802c67c"},
-    {file = "multidict-4.7.1-cp36-cp36m-win32.whl", hash = "sha256:cf14aaf2ab067ca10bca0b14d5cbd751dd249e65d371734bc0e47ddd8fafc175"},
-    {file = "multidict-4.7.1-cp36-cp36m-win_amd64.whl", hash = "sha256:3374a23e707848f27b3438500db0c69eca82929337656fce556bd70031fbda74"},
-    {file = "multidict-4.7.1-cp37-cp37m-macosx_10_13_x86_64.whl", hash = "sha256:503b7fce0054c73aa631cc910a470052df33d599f3401f3b77e54d31182525d5"},
-    {file = "multidict-4.7.1-cp37-cp37m-manylinux1_x86_64.whl", hash = "sha256:ba566518550f81daca649eded8b5c7dd09210a854637c82351410aa15c49324a"},
-    {file = "multidict-4.7.1-cp37-cp37m-win32.whl", hash = "sha256:a3721078beff247d0cd4fb19d915c2c25f90907cf8d6cd49d0413a24915577c6"},
-    {file = "multidict-4.7.1-cp37-cp37m-win_amd64.whl", hash = "sha256:e27e13b9ff0a914a6b8fb7e4947d4ac6be8e4f61ede17edffabd088817df9e26"},
-    {file = "multidict-4.7.1-cp38-cp38-macosx_10_13_x86_64.whl", hash = "sha256:12f22980e7ed0972a969520fb1e55682c9fca89a68b21b49ec43132e680be812"},
-    {file = "multidict-4.7.1-cp38-cp38-manylinux1_x86_64.whl", hash = "sha256:0c1a5d5f7aa7189f7b83c4411c2af8f1d38d69c4360d5de3eea129c65d8d7ce2"},
-    {file = "multidict-4.7.1-cp38-cp38-win32.whl", hash = "sha256:6ce55f2c45ffc90239aab625bb1b4864eef33f73ea88487ef968291fbf09fb3f"},
-    {file = "multidict-4.7.1-cp38-cp38-win_amd64.whl", hash = "sha256:cf24e15986762f0e75a622eb19cfe39a042e952b8afba3e7408835b9af2be4fb"},
-    {file = "multidict-4.7.1.tar.gz", hash = "sha256:d7b6da08538302c5245cd3103f333655ba7f274915f1f5121c4f4b5fbdb3febe"},
+    {file = "multidict-4.7.2-cp35-cp35m-macosx_10_13_x86_64.whl", hash = "sha256:8f30ead697c2e37147d82ba8019952b5ea99bd3d1052f1f1ebff951eaa953209"},
+    {file = "multidict-4.7.2-cp35-cp35m-manylinux1_x86_64.whl", hash = "sha256:824716bba5a4efd74ddd36a3830efb9e49860149514ef7c41aac0144757ebb5d"},
+    {file = "multidict-4.7.2-cp35-cp35m-win32.whl", hash = "sha256:63d9a3d93a514549760cb68c82864966bddb6ab53a3326931c8db9ad29414603"},
+    {file = "multidict-4.7.2-cp35-cp35m-win_amd64.whl", hash = "sha256:a03efe8b7591c77d9ad4b9d81dcfb9c96e538ae25eb114385f35f4d7ffa3bac2"},
+    {file = "multidict-4.7.2-cp36-cp36m-macosx_10_13_x86_64.whl", hash = "sha256:7dd6f6a51b64d0a6473bc30c53e1d73fcb461c437f43662b7d6d701bd90db253"},
+    {file = "multidict-4.7.2-cp36-cp36m-manylinux1_x86_64.whl", hash = "sha256:77264002c184538df5dcb4fc1de5df6803587fa30bbe12203a7a3436b8aafc0f"},
+    {file = "multidict-4.7.2-cp36-cp36m-win32.whl", hash = "sha256:b86e8e33a0a24240b293e7fad233a7e886bae6e51ca6923d39f4e313dd1d5578"},
+    {file = "multidict-4.7.2-cp36-cp36m-win_amd64.whl", hash = "sha256:daf6d89e47418e38af98e1f2beb3fe0c8aa34806f681d04df314c0f131dcf01d"},
+    {file = "multidict-4.7.2-cp37-cp37m-macosx_10_13_x86_64.whl", hash = "sha256:7f4e591ec80619e74c50b7800f9db9b0e01d2099094767050dfe2e78e1c41839"},
+    {file = "multidict-4.7.2-cp37-cp37m-manylinux1_x86_64.whl", hash = "sha256:335344a3c3b19845c73a7826f359c51c4a12a1ccd2392b5f572a63b452bfc771"},
+    {file = "multidict-4.7.2-cp37-cp37m-win32.whl", hash = "sha256:615a282acd530a1bc1b01f069a8c5874cb7c2780c287a2895ad5ab7407540e9d"},
+    {file = "multidict-4.7.2-cp37-cp37m-win_amd64.whl", hash = "sha256:20081b14c923d2c5122c13e060d0ee334e078e1802c36006b20c8d7a59ee6a52"},
+    {file = "multidict-4.7.2-cp38-cp38-macosx_10_13_x86_64.whl", hash = "sha256:49e80c53659c7ac50ec1c4b5fa50f045b67fffeb5b735dccb6205e4ff122e8b6"},
+    {file = "multidict-4.7.2-cp38-cp38-manylinux1_x86_64.whl", hash = "sha256:ff53a434890a16356bc45c0b90557efd89d0e5a820dbab37015d7ee630c6707a"},
+    {file = "multidict-4.7.2-cp38-cp38-win32.whl", hash = "sha256:c1c64c93b8754a5cebd495d136f47a5ca93cbfceba532e306a768c27a0c1292b"},
+    {file = "multidict-4.7.2-cp38-cp38-win_amd64.whl", hash = "sha256:e03b7addca96b9eb24d6eabbdc3041e8f71fd47b316e0f3c0fa993fc7b99002c"},
+    {file = "multidict-4.7.2.tar.gz", hash = "sha256:d4dafdcfbf0ac80fc5f00603f0ce43e487c654ae34a656e4749f175d9832b1b5"},
 ]
 mypy = [
     {file = "mypy-0.760-cp35-cp35m-macosx_10_6_x86_64.whl", hash = "sha256:ec6eaf98a57624d96d9916352a5bad2d73959f6358fabf43838f7d1a4d2f8389"},
diff --git a/pyproject.toml b/pyproject.toml
index 5bf2d68..6535d23 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,7 @@ license = "MIT"
 readme = "README.md"
 
 [tool.poetry.dependencies]
-python = "~3.6"
+python = "^3.6"
 markdown = "^3.1.1"
 fire = "^0.2.1"
 sanic = "^19.9.0"
diff --git a/tox.ini b/tox.ini
deleted file mode 100644
index 3f8fb7a..0000000
--- a/tox.ini
+++ /dev/null
@@ -1,11 +0,0 @@
-[tox]
-isolated_build = true
-toxworkdir = /opt/venv/tox
-envlist = py36
-
-[testenv]
-setenv = BUILD_ENVIRONMENT = development
-whitelist_externals = poetry
-                      make
-sitepackages = true
-commands = make dev-test-single