Laravel - Drop down value is not updating to database

Question

I was trying to update the dropdown value from user input to database here is my code-

my drop down input field in the user from -

 <div class="form-group">
      {{Form::label('userRole', 'User Role')}}
        {{Form::select('role_id', $roles ,$user->role_id,["class"=>"form-control text capitalize"])}}
 </div>

In my Controller-

public function update(UsersEditRequest $request, $id) {
     $findUser = User::findOrFail($id);
      $input = $request->all();
       $findUser->update($input);
        return redirect("admin/users");
}

so the issue is everything updates except the dropdown