Suggestions for maintaining the Event class

[hwonyo]

I suggest Maintain Event Class separately

• This separation makes code more suitable for object-oriented.
• This is more efficient way to maintain and expand code for new webhook event
• And modify features in each class efficiently.

With this separation we can clarify what we have to do for a new Event class from the facebook.
Only 3 steps are required

1. Add new event class.
2. Add new event handler.
3. Add new logic in event_parser & handle_webhook
   + test code

Here is an example of adding a new class.

• target class: messaging_game_plays
• reference: link

1. step1: Add new event class for messaging_game_plays. --> GamePlayEvent
2. step2: Add a event handler for the GamePlayEvent. --> handle_game_play
3. step3: Add elif for the game_play handler. --> in event_parser & in hadle_webhook

[coveralls]

Coverage increased (+2.8%) to 92.458% when pulling c4e7090 on HwangWonYo:modify_event into 4209c19 on conbus:master.

[coveralls]

Coverage increased (+2.8%) to 92.458% when pulling c4e7090 on HwangWonYo:modify_event into 4209c19 on conbus:master.