Execute a ruby command with rbenv's shims from the user or the system

    CLI Example:

    .. code-block:: bash

        salt '*' rbenv.do 'gem list bundler'
        salt '*' rbenv.do 'gem list bundler' deploy

def do(cmdline, runas=None, env=None):
    '''
    Execute a ruby command with rbenv's shims from the user or the system

    CLI Example:

    .. code-block:: bash

        salt '*' rbenv.do 'gem list bundler'
        salt '*' rbenv.do 'gem list bundler' deploy
    '''
    if not cmdline:
        # This is a positional argument so this should never happen, but this
        # will handle cases where someone explicitly passes a false value for
        # cmdline.
        raise SaltInvocationError('Command must be specified')

    path = _rbenv_path(runas)
    if not env:
        env = {}

    # NOTE: Env vars (and their values) need to be str type on both Python 2
    # and 3. The code below first normalizes all path components to unicode to
    # stitch them together, and then converts the result back to a str type.
    env[str('PATH')] = salt.utils.stringutils.to_str(   # future lint: disable=blacklisted-function
        os.pathsep.join((
            salt.utils.path.join(path, 'shims'),
            salt.utils.stringutils.to_unicode(os.environ['PATH'])
        ))
    )

    try:
        cmdline = salt.utils.args.shlex_split(cmdline)
    except AttributeError:
        cmdauth = salt.utils.args.shlex_split(six.text_type(cmdline))

    result = __salt__['cmd.run_all'](
        cmdline,
        runas=runas,
        env=env,
        python_shell=False
    )

    if result['retcode'] == 0:
        rehash(runas=runas)
        return result['stdout']
    else:
        return False