Ask HN: Whats a good resource to learn rails active associations?

Hi HN,

I'm in the process of learning rails and I've studied basic sql at university but I'm having a really hard time getting my head around rails active association.

For instance I'm trying to build a twitter clone. Where users can follow other users and have a homefeed populated with tweets from other users. But I can't seem to get the association of the relation mapped in my head.

If anybody could share their experience with learning Rails assocations or have any resources about it that would be fantastic.

Thanks so much