Close the database when Flamenco shuts down

This prevents SQLite journal files from lingering around.

cmd/flamenco-manager/main.go

@@ -137,6 +137,7 @@ func runFlamencoManager() bool {
 
 	// Construct the services.
 	persist := openDB(*configService)
+	defer persist.Close()
 
 	// Disabled for now. `VACUUM` locks the database, which means that other
 	// queries can fail with a "database is locked (5) (SQLITE_BUSY)" error. This

internal/manager/persistence/db.go

@@ -149,3 +149,12 @@ func (db *DB) vacuum() {
 		log.Error().Err(tx.Error).Msg("error vacuuming database")
 	}
 }
+
+// Close closes the connection to the database.
+func (db *DB) Close() error {
+	sqldb, err := db.gormDB.DB()
+	if err != nil {
+		return err
+	}
+	return sqldb.Close()
+}