cd to git_root

function gr {
    ## If the current working directory is inside of 
    ## a git repository, this function will change
    ## it to the git root (ie, the directory that 
    ## contains the .git/ directory), and then print
    ## the new directory.

    git branch > /dev/null 2>&1 || return 1
    cd "$(git rev-parse --show-cdup)".
    pwd
}