public function showAll()
 {
     $agents = Agent::whereHas('user', function ($query) {
         if (Input::has('country')) {
             $query->where('country_id', '=', Input::get('country'));
         }
         if (Input::has('platform')) {
             $query->where('platform_id', Input::get('platform'));
         }
         if (Input::has('continent')) {
             $query->whereHas('country', function ($query) {
                 $query->where('continent_id', Input::get('continent'));
             });
         }
     })->paginate(50);
     return view('agents.index', compact('agents'));
 }