Everytime I try to get all the users inside a specific classroom using its id, it returns me nothing. I have a jointable with user_id and class_id

Classroom.orm.yml
[code]
  id:
    classID:
      column: class_id
      type: integer
      generator: { strategy: AUTO }
  fields:
  manyToMany:  // <---- this is the map
    classUsers:
      targetEntity: acme\UserBundle\Entity\User
      mappedBy: userClassrooms
  oneToMany:
    classAnnouncement:
      targetEntity: acme\ClassroomBundle\Entity\Announcements
      mappedBy: announcementClass
  manyToMany:
    classLesson:
      targetEntity: CloudPod\ClassroomBundle\Entity\Lessons
      inversedBy: lessonClass
      joinTable:
        name: classroom_lessons
        joinColumns:
          fk_class_id:
            referencedColumnName: class_id
        inverseJoinColumns:
          fk_lesson_id:
            referencedColumnName: lesson_id[/code]

User.orm.yml

[code]
acme\UserBundle\Entity\User:
  type:  entity
  table: reg_user
  id:
    userID:
      column: user_id
      type: integer
      generator: { strategy: AUTO }
  fields:
...
  manyToMany: //this is the map
    userClassrooms:
      targetEntity: acme\ClassroomBundle\Entity\Classroom
      inversedBy: classUsers
      joinTable:
        name: classroom_users
        joinColumns:
          fk_user_id:
            referencedColumnName: user_id
        inverseJoinColumns:
          fk_class_id:
            referencedColumnName: class_id
[/code]

Classroom.php
[code]
...
public function __construct()
    {
        $this->classUsers = new ArrayCollection();
//other array collections
        $this->classAnnouncement = new ArrayCollection();
        $this->classLesson = new ArrayCollection();
    }
    public function addClassUser(\CloudPod\UserBundle\Entity\User $classUsers)
    {
        $this->classUsers[] = $classUsers;
           return $this;
    }

    public function removeClassUser(\CloudPod\UserBundle\Entity\User $classUsers)
    {
        $this->classUsers->removeElement($classUsers);
    }
    public function getClassUsers()
    {
        return $this->classUsers;
    }[/code]

Controller
[code]public function StudentClassroomAction($classID)
    {

    	$class_repository = $this->getDoctrine()->getRepository('CloudPodClassroomBundle:Classroom');
    	$classroom = $class_repository->find($classID); //im sure this stores an object of classroom
        $userinfo = $classroom->getClassUsers(); //THIS IS THE THING!!!
//first i tried rendering it in twig. still gives me nothing
/*return $this->render('CloudPodClassroomBundle:Classrooms:Student.html.twig',array(
    		'classroom' => $classroom,
    		'classuser' => $userinfo));
			*/
//I change it to response to know if something is stored in $userinfo it returns an empty page rather than an error.Then $userinfo still has no object stored.
        return new response($userinfo);


    }[/code]

tbl: classroom_users
__________________________
|  fk_user_id   |  fk_class_id  |
------------------------------------
|        1           |         1         |
|       2            |         1         |
------------------------------------

Can anybody tell me, whats wrong? I really cant pinpoint which is which specially now since it doesn't return any error to me.