Add DittoDB module for selecting a database depending on the DATABASE_URL

src/db/DittoDB.ts

@@ -0,0 +1,17 @@
+import { Conf } from '@/config.ts';
+import { DittoSQLite } from '@/db/adapters/DittoSQLite.ts';
+import { DittoTables } from '@/db/DittoTables.ts';
+import { Kysely } from '@/deps.ts';
+
+export class DittoDB {
+  static getInstance(): Promise<Kysely<DittoTables>> {
+    const { databaseUrl } = Conf;
+
+    switch (databaseUrl.protocol) {
+      case 'sqlite:':
+        return DittoSQLite.getInstance();
+      default:
+        throw new Error('Unsupported database URL.');
+    }
+  }
+}