Laravel Model Relations between 3 tables

I am currently trying to make a relation between 3 tables.

Users
    uid
    username
Groups
    gid
    groupname
GroupMembers
    uid
    gid

With eloquent ORM, how do I get the Groups of a User?
With just 1 line of query I wanted to return a json reply like: (search group that I am a member of... keyword: Admin)

Status 200
User   uid 1
       username mrwootwoot

       Groups
            {
             gid 1
             groupname administrators
            }
            {
             gid 2
             groupname wadmin
            }

What I got so far is:

$joined_networks = User::whereHas('groups', function($q)
{
    $q->where('is_blocked', '=', 0)->where('name','like',"%admin%");
})->with('groups')->where('uid', $user_id)->get();

(...)

return Response::json(array(
    'status' => 200,
    'user' => $joined_networks->toArray()
));

This part of the code is suppose to find the groups the user is a member of where he is not blocked.

update

$joined = User::with('group')->where('uid', $user_id)->get();

return Response::json(array(
    'status' => 200,
    'results' => $joined
));

and my user model:

public function group()
{
    return $this->hasManyThrough('Group', 'GroupMembers', 'uid', 'gid');
}

Now it just returns nothing

{
    "status": 200,
    "results": {

    }
}

update

$user = User::find($user_id);
$user_groups = $user->groups();

return Response::json(array(
    'status' => 200,
    'results' => $user_groups
));

But still the same as above, no result being given back.

update It was a mistake on the output. $user_groups->toArray() is the right one. Works well now.