Merge pull request #4 from milica-nerlovic/master

Add basic info about distillery to README

README.md

@@ -1,6 +1,6 @@
 # Alpine Release
 
-Generate an distillery release for Alpine Docker with ease.
+Generate a distillery release for Alpine Docker with ease.
 
 ## Installation
 
@@ -15,6 +15,37 @@ def deps do
 end
 ```
 
+## Working with distillery
+
+Run:
+
+```bash
+mix release.init
+```
+to generate `rel/config.exs` configuration file. This file is used by distillery
+to build you release, so make sure you have it checked in your version control
+system if you plan to build your releases remotely.
+
+More info about the configuration can be found on [Distillery
+docs](https://hexdocs.pm/distillery/configuration.html).
+
+### Notable differences from exrm
+
+Distillery has some differences compared to
+[exrm](https://github.com/bitwalker/exrm) in respect to replacing OS variables
+in your Dockerfiles.
+
+This will work:
+```bash
+REPLACE_OS_VARS=true
+```
+but this won't:
+```bash
+RELX_REPLACE_OS_VARS=true
+```
+
+For more info, check out [distillery github repo](https://github.com/bitwalker/distillery).
+
 ## Generate a release
 
 ``` bash