Merge branch 'master' into add-code-of-conduct-1

Author: apdjz

CONTRIBUTING.md

@@ -0,0 +1,7 @@
+## Contribution guide
+
+- Make an issue (or multiple issues)
+- Merge master into the branch before Pull Request to make sure that there are NO conflicts
+- Make a Pull Request that references that issue
+- Get it code reviewed by someone on the team, address any comments
+- Merge into master (with merge commit)