Add a note on deleting old merged branches

[anenadic]

Question on cleaning up old git branches - is it safe to do so?
A: yes, if the features are all merged - mention the cleaning phase (deleting old branches once they have been merged) in the text?

Q: git/GitHub housekeeping: should you delete old branches once they have been merged in and are no longer being used?
A: Yes - it is a good idea to keep on top of branch house-keeping both locally and in your remote repository! You may want to remove branches once they have been merged in and are no-longer being used or branches containing content you wish to abandon. A good starter discussion can be found here: https://railsware.com/blog/git-housekeeping-tutorial-clean-up-outdated-branches-in-local-and-remote-repositories/