Delete entry if registration is cancelled

[jamestiotio]

The Firestore Database entry for a specific user_id should be deleted if they cancelled the registration process:

hostelhunt/app.py

Lines 338 to 343 in f9e496d

	# Cancel function for registration conversation
	def cancel(bot, update):
	bot.send_message(chat_id=update.message.chat_id,
	text='The current registration process has been cancelled.')
	return ConversationHandler.END

Or if they sent a student_id that has already been registered:

hostelhunt/app.py

Lines 207 to 209 in f9e496d

	else:
	if int(student_id) in pb.get_all_current_student_id():
	msg = "Student ID already registered!"

This is to not clutter the database with unnecessary entries. A new function in firebase_connector.py would need to be created to delete entries, which would be called at the corresponding aforementioned conditions.