Add commit-msg git hook

[boarpig]

It would be convenient to have commit-msg hook for git which would work like this.

If commit message matches regex (or something similar)

^([Cc]loses|[Ff]ixes) +#(\d+)

It could check if issue file is added and if it is not, it would close the issue automatically and add the file before commit. Similar to what gitlab does on push.