Add current virtualenv and git branch to shell prompt

.git_and_virtualenv.bash

#!/bin/bash
#
# Take your boring old prompt from this:
#     matthew-morrisons-macbook:~$
# and cd into a git repo and add the current branch to the prompt for a more glorious experience:
#     matthew-morrisons-macbook:django-media-masher(master)$
# then use `workon` to select a virtualenv and it will be added your prompt for additional glory:
#     (media-masher)matthew-morrisons-macbook:django-media-masher(master)$
# then freely switch branches and virtualenvs and have your prompt always reflect what you're
# currently working with
#
# make sure you do this first:
# copy git-completion.bash from git's source in contrib/completion into your home directory
# install the virtualenv and virtualenvwrapper python packages
# add the following to your bashrc
#     source ~/.git_and_virtualenv.bash

#Setup virtualenvwrapper
export WORKON_HOME=$HOME/.virtualenvs
export VIRTUALENVWRAPPER_PYTHON=/usr/local/bin/python
export VIRTUALENVWRAPPER_VIRTUALENV=/usr/local/bin/virtualenv
export VIRTUALENVWRAPPER_LOG_DIR="$WORKON_HOME"
export VIRTUALENVWRAPPER_HOOK_DIR="$WORKON_HOME"
source /usr/local/bin/virtualenvwrapper.sh

#Setup git completion
source ~/.git-completion.bash

#Hijack cd and modify PS1 to include the current git branch
function cd(){
    builtin cd $@
    export PS1='\h:\W$(__git_ps1 "(%s)")\$ '
}