Add prepush hook checking for master and stable branches

[emilgoldsmith]

Related Issue

N/A

Description

I've been accidentally pushing to master too much recently lol, so found a prepush hook online (as I can't seem to ban admins from pushing to protected branches <.<), and while I could've just put it in a local hook, I thought it might be nice for other admins too.

How Has This Been Tested?

N/A (well I tested it manually by running the grep and checking the output and by changing the current_branch variable to harddcoded master and checked that it prompted me)

Screenshots (if appropriate):

N/A

Checklist:

All of this is N/A :)

• [x] My code follows the code style of this project. (see the style guide)
• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] I have added tests to cover my changes.

[coveralls]

Coverage remained the same at 5.824% when pulling 27eba422d7bc8f3943eb289461130086c76831e1 on emil/warn-on-master-push into 1f3da7354c94b125c596c92b9612a898ac3e8ad6 on master.

[emilgoldsmith]

There we go @Helw150, much nicer now :)

(Also, I promise I'm not having Ghost nostalgia, it was just what came up when I googled :P)