Add a last change footer to the implementers guide

roadmap/implementers-guide/README.md

@@ -20,6 +20,8 @@ Then install and build the book:
 
 ```sh
 cargo install mdbook mdbook-linkcheck mdbook-graphviz mdbook-mermaid
+# This plugin is not available on crates.io yet.
+cargo install --git https://github.com/badboy/mdbook-last-changed/ --rev 2448157
 mdbook serve roadmap/implementers-guide
 open http://localhost:3000
 ```

roadmap/implementers-guide/book.toml

@@ -9,8 +9,14 @@ title = "The Polkadot Parachain Host Implementers' Guide"
 command = "mdbook-graphviz"
 [preprocessor.mermaid]
 command = "mdbook-mermaid"
+[preprocessor.last-changed]
+command = "mdbook-last-changed"
+renderer = ["html"]
 
 [output.html]
+additional-css = ["last-changed.css"]
 additional-js = ["mermaid.min.js", "mermaid-init.js"]
+# Repository URL used in the last-changed link.
+git-repository-url = "https://github.com/paritytech/polkadot"
 
 [output.linkcheck]

roadmap/implementers-guide/last-changed.css

@@ -0,0 +1,7 @@
+footer {
+    font-size: 0.8em;
+    text-align: center;
+    margin-top: 50px;
+    border-top: 1px solid black;
+    padding: 5px 0;
+}

scripts/ci/gitlab/pipeline/build.yml

@@ -171,6 +171,8 @@ build-implementers-guide:
   script:
     - apt-get -y update; apt-get install -y graphviz
     - cargo install mdbook mdbook-mermaid mdbook-linkcheck mdbook-graphviz
+    # This plugin is not available on crates.io yet.
+    - cargo install --git https://github.com/badboy/mdbook-last-changed/ --rev 2448157
     - mdbook build ./roadmap/implementers-guide
     - mkdir -p artifacts
     - mv roadmap/implementers-guide/book artifacts/