[Add New Feature Collab] Recommend Top N for Item/User

Hi Dev Team,

I want to help contribute FastAI by adding a collab feature. Sometimes when using recomendation engine, we want to recommend top N product for a particular user, when this user visit particular movie/product page in real time. In other case, we sometimes also want to create whitelist users for campaign for a product. So this feature target both goals.

Reading some dev guidelines documentation, I’m expected to create a notebook so others can understand how we can use this feature.

Here is the gist of the notebook. https://gist.github.com/napjon/c47d62c08619d16278ea8eba4a5c1c69

Let me know what are your thought/suggestion.