Hello! Long time user of miniflux. Finally upgraded to v2. In my miniflux V1 OPML export, I notice that some feeds have multiple category assignments. This was previously available in the V1 UI. This OPML successfully imports into miniflux V2. However, I am unable to edit multiple category assignments, and also unable to assign new feeds to more than one category.

I feel this is a feature that should be incorporated back into miniflux as it is supported both by OPML and Fever API. This is different from #283 as there is no parent/child relationship, just single level, single feed to one or many categories. It is similar to #335, but it is not redefining the relationship between feeds and categories. This feature could also resolve #346 as categories could be selected/deselected as desired from each feed.

I appreciate your time, and thank you for many years of such a wonderful open source project.