The docs now show the version number.

The change turned out to be simple, just adding `./docs/_data/version.yml` file with the version number in it. Additionally, added `./docs/_include/nav_footer_custom.html`, which is a simple Liquid tag to read the version file.
This change will necessitate coming up with a solution to keep the code version number in .`/src/tbp/__init__.py` and the new YAML file in sync.
Also updated the `makefile` to use `bundle exec` in front of the documentation commands. That was not clearly spelled out in the Jekyll docs.

Closes #4.

.vscode/settings.json

@@ -56,6 +56,7 @@
         "Hillery",
         "Imigrantes",
         "ITTY",
+        "jemoji",
         "Jonny",
         "José",
         "Kabhi",
@@ -67,6 +68,7 @@
         "Libertadores",
         "Lookin",
         "López",
+        "mathjax",
         "maxfail",
         "megamouth",
         "Mitbestimmungsgesetz",

Makefile

@@ -27,6 +27,6 @@ lint:
 
 .PHONY: docs
 docs:
-	cd docs; jekyll build; jekyll serve --livereload; cd ..
+	cd docs; bundle exec jekyll build; bundle exec jekyll serve --livereload; cd ..
 
 all: mypy lint tests

docs/_data/version.yml

@@ -0,0 +1 @@
+number: 0.9.0

docs/_includes/nav_footer_custom.html

@@ -0,0 +1,5 @@
+<!-- Puts the tbp version in the navigation footer.  -->
+ <footer class="site-footer">
+  tbp version : {{site.data.version.number}}
+</footer>
+