[contributing] Enhance the documentation.

CONTRIBUTING.md

@@ -9,17 +9,44 @@ Please follow these rules when contributing code to famedly talk:
 - Only Merge Requests with a working CI can be merged.
 - Only Merge Requests with at least one code reviewer can be merged.
 - Merge Requests may be refused if they don't follow the rules below.
+- A new Merge Request SHOULD never decrease the test coverage.
+
+## Branches
+### Naming
+
+Branches should get named by this pattern: `[Module Name]-[Type]-[Detail]`.
+
+That means for example: "users-fix-attach-roles-issue#765".
+
+Modules are various parts of the App. This can for example be the directory list or the chat room.
+
+Types can be one of these:
+- **feature**
+- **enhance**
+- **cleanup**
+- **refactor**
+- **fix**
+- **hotfix** (should rarely get used)
+
+The Detail part of the pattern should be a short description of what the branch delivers.
+
+## Commit Messages
+
+Commit Messages should get written in this pattern: `[[Module Name]] [Commit Message]`.
+
+That means for example: "[users] add fetch users endpoint".
+
 
 ## File structure:
 - Every file must be named by the class and must be capitalized in the beginning.
 - Directories need to be lowercase.
 
 ## Code style:
-- We recommend to use Android Studio for coding. We are using the Android Studio auto styling with ctrl+alt+shift+L.
+- We recommend using Android Studio for coding. We are using the Android Studio auto styling with ctrl+alt+shift+L.
 
 ## Code quality:
 - Don't repeat yourself! Use local variables, functions, classes.
-- Don't mix UI and business logic in the same enivornment.
+- Don't mix UI and business logic in the same environment.
 - Write tests for new classes, functions and widgets.
 - Keep it simple stupid: https://en.wikipedia.org/wiki/KISS_principle
 - Describe all of your classes, methods and attributes using **dartdoc** comments. Read this for more informations: https://dart.dev/guides/language/effective-dart/documentation