anchor.diff:        extra_headers => "Location: /playlists\r\n",
         return_code   => "303 See Other"}.
   
  -handle_register_post(Data, _Parameters, _Headers) ->
  +handle_register_post(Data, _Parameters, _Headers, InstanceName) ->
       PostParameters = http_parser:parameters(Data),
       {"username", Username} = lists:keyfind("username", 1, PostParameters),
       {"password", Password} = lists:keyfind("password", 1, PostParameters),
       Result   = reg_user(Username, Password),
       case Result of
           user_registered ->
  -            case check_login(Username, Password) of
  +            case check_login(Username, Password, InstanceName) of
                   login_fail ->
                       <<"Registrering gick okej, men login gick inte bra...">>;
                   {login_ok, Cookie} ->
  
positive.code:             case Password == DBPassword of
                  false -> login_fail;
                  true  ->
                      add_to_active_users(Username),
                      HtmlEncode = encrypt(Username),
                      C = "Set-Cookie: username=" ++ HtmlEncode ++ "\r\n",
                      {login_ok, C}
  
negative.code:               return_code   => "303 See Other"}
      end.
  
  handle_delete_song(_Data, Parameters, Headers, InstanceName) ->
      case is_logged_in(Headers, InstanceName) of
          false ->
              render_not_logged_in();
          _Username ->
  