postactivate hook for virtualenvwrapper to add a project's `bin` directory to the path while the venv is active.

gistfile1.sh

get_project_dir () {
    virtualenvwrapper_verify_workon_home || return 1
    virtualenvwrapper_verify_active_environment || return 1
    if [ -f "$VIRTUAL_ENV/.project" ]
    then
        project_dir=$(cat "$VIRTUAL_ENV/.project") 
        if [ ! -z "$project_dir" ]
        then
            # will be cleaned up by virtualenvwrapper
            export PATH="${project_dir}/bin/:$PATH"
            # find new programs (possibly ZSH specific)
            hash -r
        fi
    fi
    return 0
}
get_project_dir