Storing metadata for searching

[sd14]

Hello,

I'm building an app for my three friends and I. We listen to an album a week and talk about it. I want to store the album we listen to, the artist info, tracks, etc, so we can give each album a one to five star rating and pick our favorite and least favorite songs. 

In order to make searching the database easier (for things such as most popular album liked by a certain person, or a persons favorite artist) I would like to store the data in MongoDB. 

I see that in the Terms of Service it says the data can be saved locally if it is necessary. I know this is a bit of an unusual use for the API. I just want to clarify if this use case is okay.

Thank you