This is to let the author of the post know, that this pod is interested
in updates about this post.
The sending user is only used to verify that the participation was sent
from this pod, but lets use an admin/podmin account if available.
closes#7708
This commit introduces support for AccountMigration federation message
receive. It covers the cases when the new home pod for a user is remote
respective to the recepient pod of the message. It also allows to initiate
migration locally by a podmin from the rails console. This will give the
pods a possibility to understand the account migration event on the
federation level and thus future version which will implement migration
will be backward compatible with the pods starting from this commit.
We can determine diaspora_handle from a relation with people for the
shareables (posts, photos). So we don't need to store diaspora_handle in
the DB. Also remove tmp_old_id from photos which is not refenrenced anywhere.
