Add join_room method back

app/controllers/room_requests_controller.rb

@@ -9,7 +9,7 @@ def index
   end
 
   def accept
-    current_user.room.users << @request.sender
+    @request.sender.join_room(current_user.room)
     redirect_to dashboard_path, notice: "#{@request.sender.name} successfully joined your room."
   end
 

app/controllers/rooms_controller.rb

@@ -15,7 +15,7 @@ def create
     @room = Room.new(room_params)
 
     if @room.save
-      @room.users << current_user
+      current_user.join_room(@room)
       @room.create_default_room_activities
       redirect_to new_room_activity_path, notice: "You have successfully created new room \"#{@room.name}\"."
     else
@@ -45,7 +45,7 @@ def join
                          notice: 'To join another room you need to leave your current. You can do this in danger zone.'
     end
     room = Room.with_invite_token(params[:token])
-    room.users << current_user
+    current_user.join_room(room)
     redirect_to dashboard_path, notice: "Welcome to room \"#{room.name}\"!"
   end
 

app/models/user.rb

@@ -34,6 +34,10 @@ def next_on_room_activities
     room_activities.select { |room_activity| room_activity.next_on_user == self }
   end
 
+  def join_room(room)
+    room.users << self
+  end
+
   def leave_room
     activities.destroy_all
     update(room: nil)