Updated How to contribute (markdown)

docs/content/how-to-contribute.md

@@ -1,14 +1,21 @@
-Contribution is like any other GitHub project:
+`docker-mailserver` is OpenSource. That means that you can contribute on enhancements, bug fixing or improving the documentation in the Wiki.
-
-- Fork
-- Improve
-- Add integration tests in `test/tests.bats`
-- Build image and run tests using `make`
-- Document your improvements
-- Commit, push and make a pull-request
 
 #### Project architecture
 
     ├── config                    # User: personal configurations
     ├── target                    # Developer: default server configurations
     └── test                      # Developer: integration tests
+
+#### Development Workflow
+
+When `v2` will be released, the development workflow will be:
+
+- Fork
+- Improve
+- Add integration tests in `test/tests.bats`
+- Use `make` to build image locally and run tests
+- Document your improvements
+- Commit, push and make a pull-request on `develop` branch
+- When tests are green, your branch is merged and tested on real servers by contributors
+- When feedback is positive, develop is merged on master
+