Move docs to mkdocs and improve them

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

docs/contribute/styleguide.md

@@ -0,0 +1,29 @@
+# Styleguide
+
+## Elixir
+
+We format our code with the Elixir Formatter and check for issues with [Credo](https://github.com/rrrene/credo) (a few rules are not blocking).
+
+Please run these two commands before pushing code:
+
+ * `mix format`
+ * `mix credo`
+ 
+These two commands must not return an error code, since they are required to pass inside CI.
+
+## Front-end
+
+### Linting
+
+We use `tslint` and `eslint` with the `airbnb` preset.
+Errors should be reported when the development server is running or when building a production bundle `yarn run build`.
+
+Please run the following command before pushing code `yarn run lint`.
+
+This command must not return an error code, since it's required to pass inside CI.
+
+We also try to follow the [official Vue.js style guide](https://vuejs.org/v2/style-guide/).
+
+### Styleguide
+
+We present the components used on Mobilizon's front-end here: https://framasoft.frama.io/mobilizon/frontend/. The documentation is builded through [Vue Styleguidist](https://vue-styleguidist.github.io/)