A simple command line tool to open your browser to a GitHub pullrequest page.
Install: sudo npm install -g pullrequest
Then run pullrequest to open your browser with the diff from your current branch to your GitHub default branch (master).
To change the target branch run pullrequest to release3 to open your browser with a diff from your current branch to release3.
To use a github remote other than origin you can add a pullrequest origin like this: git remote add pullrequest git@github.com:me/myrepo.git.