- each feed can have multiple groups assigned
- group assignments are done on the add or edit feed page
- groups are only visible on the unread page
- groups are exported via the fever api
- it's not possible do delete a group manually from the database (the group will be removed automatically, as soon as the last association of a group to a feed is removed)
- if you try to create an already existing group, the existing group is used to prevent duplicates
