Minor logic error in recommendation_system_tutorial/recommendation_system_tutorial_netflix.py

[oyzh888]

This line :
top_similar_user_ratings.extend([global_avg_rating[movie]] * (5 - len(ratings)))
should be
top_similar_user_ratings.extend([global_avg_rating[movie]] * (5 - len(top_similar_user_ratings)))

Because len(ratings) is a const large value here which is not right.

https://github.com/towardsai/tutorials/blob/master/recommendation_system_tutorial/recommendation_system_tutorial_netflix.py#L174