Remove unique key constraint on foreign key user_id in mfa table

setup/mail-users.sh

@@ -22,7 +22,7 @@ if [ ! -f $db_path ]; then
 	echo Creating new user database: $db_path;
 	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 UNIQUE, 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 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;
 fi
 
 # ### User Authentication

setup/migrate.py

@@ -184,7 +184,7 @@ def migration_12(env):
 def migration_13(env):
 	# Add the "mfa" table for configuring MFA for login to the control panel.
 	db = os.path.join(env["STORAGE_ROOT"], 'mail/users.sqlite')
-	shell("check_call", ["sqlite3", db, "CREATE TABLE mfa (id INTEGER PRIMARY KEY AUTOINCREMENT, user_id INTEGER NOT NULL UNIQUE, type TEXT NOT NULL, secret TEXT NOT NULL, mru_token TEXT, label TEXT, FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE);"])
+	shell("check_call", ["sqlite3", db, "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);"])
 
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