Merge pull request #579 from lukeboyett/fix/db-transaction-type

fix(db): declare transaction() on local Database interface

src/db.ts

@@ -69,6 +69,7 @@ export interface Database {
   exec(sql: string): void;
   prepare(sql: string): Statement;
   loadExtension(path: string): void;
+  transaction<T extends (...args: any[]) => any>(fn: T): T;
   close(): void;
 }