Add CONTRIBUTING file
Add CONTRIBUTING file

Copied from Lucy with minor adjustments.

rectang/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish,apache/lucy-clownfish,rectang/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish,apache/lucy-clownfish,apache/lucy-clownfish,apache/lucy-clownfish,nwellnhof/lucy-clownfish,apache/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,rectang/lucy-clownfish,nwellnhof/lucy-clownfish,apache/lucy-clownfish,apache/lucy-clownfish,apache/lucy-clownfish,rectang/lucy-clownfish