Move automatically generated aliases to a separate database table

They really should never have been conflated with the user-provided aliases.

Update the postfix alias map to query the automatically generated aliases with lowest priority.

setup/mail-users.sh

@@ -23,6 +23,7 @@ if [ ! -f $db_path ]; then
 	echo "CREATE TABLE users (id INTEGER PRIMARY KEY AUTOINCREMENT, email TEXT NOT NULL UNIQUE, password TEXT NOT NULL, extra, privileges TEXT NOT NULL DEFAULT '');" | sqlite3 $db_path;
 	echo "CREATE TABLE aliases (id INTEGER PRIMARY KEY AUTOINCREMENT, source TEXT NOT NULL UNIQUE, destination TEXT NOT NULL, permitted_senders TEXT);" | sqlite3 $db_path;
 	echo "CREATE TABLE mfa (id INTEGER PRIMARY KEY AUTOINCREMENT, user_id INTEGER NOT NULL, type TEXT NOT NULL, secret TEXT NOT NULL, mru_token TEXT, label TEXT, FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE);" | sqlite3 $db_path;
+	echo "CREATE TABLE auto_aliases (id INTEGER PRIMARY KEY AUTOINCREMENT, source TEXT NOT NULL UNIQUE, destination TEXT NOT NULL, permitted_senders TEXT);" | sqlite3 $db_path;
 fi
 
 # ### User Authentication
@@ -145,7 +146,7 @@ EOF
 # empty destination here so that other lower priority rules might match.
 cat > /etc/postfix/virtual-alias-maps.cf << EOF;
 dbpath=$db_path
-query = SELECT destination from (SELECT destination, 0 as priority FROM aliases WHERE source='%s' AND destination<>'' UNION SELECT email as destination, 1 as priority FROM users WHERE email='%s') ORDER BY priority LIMIT 1;
+query = SELECT destination from (SELECT destination, 0 as priority FROM aliases WHERE source='%s' AND destination<>'' UNION SELECT email as destination, 1 as priority FROM users WHERE email='%s' UNION SELECT destination, 2 as priority FROM auto_aliases WHERE source='%s' AND destination<>'') ORDER BY priority LIMIT 1;
 EOF
 
 # Restart Services