feat: full group support

migrations/each_user/0007_contact-groups.sql

@@ -2,3 +2,8 @@ create table if not exists groups (
 	contact_id integer not null references contacts(id) on delete cascade,
 	name text not null
 );
+
+alter table contact_mentions rename to journal_mentions;
+alter table journal_mentions add column url text not null default '';
+update journal_mentions set url = '/contact/'||contact_id;
+alter table journal_mentions drop column contact_id;