Better docs

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

Nicer docs

No 3rd stage

Add mix.deps get before docs

Add :ex_doc on test env so that it runs into CI

support/guides/development/tests.md

@@ -0,0 +1,36 @@
+# Tests
+
+## Backend
+
+The backend uses `ExUnit`.
+
+To launch all the tests:
+```bash
+mix test
+```
+
+If you want the coverage:
+
+```bash
+mix coveralls.html
+```
+
+It will show the coverage and will output a `cover/excoveralls.html` file.
+
+If you want to test a single file:
+
+```bash
+mix test test/mobilizon/actors/actors_test.exs
+```
+
+If you want to test a specific test, block or line:
+
+```bash
+mix test test/mobilizon/actors/actors_test.exs:85
+```
+
+> Note: The coveralls.html also works the same
+
+## Front-end
+
+Waiting for [https://framagit.org/framasoft/mobilizon/merge_requests/42](https://framagit.org/framasoft/mobilizon/merge_requests/42) to be ready.