Alias git -> hub for pull-request support

Signed-off-by: Evan Owen <kainosnoema@gmail.com>
Add git alias pr -> pull-request to make PRs easier

Signed-off-by: Evan Owen <kainosnoema@gmail.com>
Add git update alias for finishing up merged branches

Signed-off-by: Evan Owen <kainosnoema@gmail.com>