Add `github fetch <user> <branch>` command.
Add `github fetch <user> <branch>` command.

This will create a remote for <user>, fetch the branch into refs/remotes/<user>/<branch> and then create a local branch from that. This is good for getting an exact copy of the branch (without merging it into another branch) for local testing or inspection.

rlqualls/github-gem,jarib/github-gem,supriyantomaftuh/github-gem,reenhanced/github-gem,kohsuke/github-gem,thetaxman/github-gem,dustin/github-gem,Wirachmat/github-gem,defunkt/github-gem,peterkinalex/github-gem,DarcRanger/github-gem