def post(self):
        '''
            Adds a movie to the users' Watchlist.
        '''
        TokenAuthenticator(request.headers.get('Authorization')).authenticate()
        movieID = request.json.get('movieID')

        is_valid_integer(movieID)

        new_watchlist = Watchlist(movieID, g.userID)
        session = Session()
        session.add(new_watchlist)
        try:
            session.commit()
            session.close()
        except IntegrityError:  #If Watchlist already present
            session.rollback()
            raise BadRequest

        response = {'message': 'Movie added to Watchlist.'}
        return response, 201
    def post(self):
        '''
            Subscribe to the user.
        '''
        TokenAuthenticator(request.headers.get('Authorization')).authenticate()
        subscribedUserID = request.json.get('userID')
        curUserID = g.userID

        # Can't subscribe to oneself.
        if curUserID == int(subscribedUserID):
            raise BadRequest

        subscribe = Subscription(curUserID, subscribedUserID)
        session = Session()
        session.add(subscribe)
        try:
            session.commit()
        except IntegrityError:  #If subscription already present
            session.rollback()
            raise BadRequest

        response = {'message': 'Subscribed to User'}
        return response, 201