Cannot insert the value NULL into column 'user_id', table 'dbo.role_user'; column does not allow nulls

I am using Zizaco/Entrust in Laravel 5.0 to apply RBAC and i'm having the following error:

Cannot insert the value NULL into column 'user_id', table 'dbo.role_user'; column does not allow nulls. INSERT fails. (SQL: insert into [role_user] ([role_id], [user_id]) values (2, ))

I followed all the steps to implement Entrust and at my User.php store method i have:

public function store(UserRequest $request)
{
    $user = new User();
    $user->create($request->all());
    $roles=$request->get('role_id');
    $user->roles->attach($roles);
    return redirect('users');
}

I want to know how can I fix this issue. All the help is appreciated.

Solution

Extra info: Entrust needs a userid to be able to assign a role to the user. When you create a user there is no userid cause a userid will be created when you create the user. So after creating the user you need to retrive the user first before you can assign it to a role.

Here: See the second code block from this URL: Entrust Github. They receive the user first and then assign it to a role.

First create the user like this:

User::create($request->all());

Then grab the newly created user like this:

$User = User::where('username', '=', $request->username)->first();

Then assign the user to the role like this:

$User->roles()->attach($request->roleid);//parenthesis missing

All together:

public function store(UserRequest $request)
{
    User::create($request->all());

    $User = User::where('username', '=', $request->username)->first();

    $User->roles()->attach($request->roleid);

    return redirect('users');
}