public function postStore($frase_id = '')
 {
     $user = User::fromToken();
     $frase = new FraseAsignatura();
     $frase->alumno_id = Request::input('alumno_id');
     $frase->asignatura_id = Request::input('asignatura_id');
     $frase->periodo_id = $user->periodo_id;
     if ($frase_id == '') {
         $frase->frase = Request::input('frase');
     } else {
         $frase->frase_id = $frase_id;
     }
     $frase->save();
     $frases = FraseAsignatura::deAlumno($frase->asignatura_id, $frase->alumno_id, $user->periodo_id);
     return $frases;
 }