db/events: don't add tags to query unless they exist

src/db/events.ts

@@ -43,9 +43,11 @@ function insertEvent(event: Event): Promise<void> {
       return results;
     }, []);
 
+    if (tags.length) {
       await trx.insertInto('tags')
         .values(tags)
         .execute();
+    }
   });
 }