larvel create MD5Hasher
Using md5() over bcrypt() is not recommended.
However you can manually authenticate user. Override login()
method in LoginController
  public function login(Request $request)
  {
     $user = User::where('username', $request->username)
                  ->where('password',md5($request->password))
                  ->first();
     Auth::login($user);
     return redirect('/');
  }
