Update for Vundle's new interface

* Vundle now lives at gmarik/Vundle.vim

See https://github.com/gmarik/Vundle.vim/blob/master/doc/vundle.txt#L345-L369
Make it easy to checkout GitHub pull requests

This alias makes the following workflow possible:

Look at changes:

    git co-pr 123
    git diff origin/master

Bundle, validate tests are passing:

    bundle
    rake

Rebase interactively, squash, and potentially improve commit messages:

    git rebase -i master

Merge code into master:

    git checkout master
    git merge pr/123 --ff-only

Push:

    git push origin master

Clean up:

    git branch -D pr/123
Allow personal overrides to psqlrc

I wanted to add my own customizations after reading @mike-burns' post on
[`psqlrc`](http://robots.thoughtbot.com/an-explained-psqlrc).

As a result of this change, `.psqlrc` requires that a `.psqlrc.local` exist in
the home folder because `psql` cannot do conditional sourcing of files in the
style that we use in other foundation dotfiles. Touching the file to ensure it
exists (even if blank) prevents `psql` from exiting with an error if the user
does not provide their own custom configuration.