Algorithm to get suggestions from items related to another

I would like to get some tips to create an efficient algorithm.

This is the scenario. I'm using rails and sqlite.

There're articles with many custom properties (or rows), in a one-to-many relation. Some properties are the same and are in common among articles and often many articles have three or more equal properties.

When creating a new article and inserting the first property, I would the app to suggest the most frequent properties existing in articles related to the first property in the other articles. So, after adding the second property, the app should suggest the most frequent properties existing in articles that contain both the two properties.

Any idea? Some libs already fitting it?