Added Overcommit and configured Rubocop

[ipepe]

I suggest that You start using overcommit.

[rastating]

I'm going to close this one for now - due to the nature of the project, there's always going to be a number of Rubocop issues that come up (some exploits naturally end up quite bloated / messy). I'll consider re-visiting this though, if there ends up being frequent contributors in the future :)

[ipepe]

@rastating That makes me very sad :(

[rastating]

The PR still counts towards your Hacktoberfest quota though, so don't worry about that :smile:

[ipepe]

I care more about good quality of code than my PR's I have got plenty enough of them.