Update software development

pages/Softwaredevelopment.md

@@ -45,7 +45,27 @@ Optional but highly recommended CI jobs to automate are:
 
 ## Development Process
 
-*TODO*
+The main development branch is the `master` branch on Git and is meant to refer
+to the latest stable version of the software. New features, experimental
+implementations and bug fixing is done on separate branches and eventually
+merged back to `master` after a code review and approvals of at least two
+additional developers. The CI makes sure that the software is working as
+expected and also indicates when the code coverage -- the fraction of untested
+parts of the software -- is decreased upon a merge.
+A separate job in the pipeline is set up to check the coding style automatically
+and ensures a common style among the whole project.
+
+To keep track of important additions, changes, bug fixes and deprecations, a
+`CHANGELOG` is available and updated accordingly. This files serves as an
+overview for the users to keep track of the development process without spending
+too much time to browse through closed issues and merge requests.
+
+The versioning follow the Semantic Versioning 2.0.0 (https://semver.org)
+conventions which indicates possible complications in up- or downgrading. The
+version number consists of three parts in form of `MAJOR.MINOR.PATCH`, where
+`MAJOR` is increased on incompatible API changes, `MINOR` when new functionality
+is added in a backwards compatible manner and `PATCH` for anything else, like
+bug fixes or cosmetics etc.
   
 ## Python Project Template