tags: delete command/response msg if the other is deleted

src/migrations/1546770935261-CreateTagResponsesTable.ts

@@ -0,0 +1,59 @@
+import { MigrationInterface, QueryRunner, Table } from "typeorm";
+
+export class CreateTagResponsesTable1546770935261 implements MigrationInterface {
+  public async up(queryRunner: QueryRunner): Promise<any> {
+    await queryRunner.createTable(
+      new Table({
+        name: "tag_responses",
+        columns: [
+          {
+            name: "id",
+            type: "int",
+            unsigned: true,
+            isGenerated: true,
+            generationStrategy: "increment",
+            isPrimary: true
+          },
+          {
+            name: "guild_id",
+            type: "bigint",
+            unsigned: true
+          },
+          {
+            name: "command_message_id",
+            type: "bigint",
+            unsigned: true
+          },
+          {
+            name: "response_message_id",
+            type: "bigint",
+            unsigned: true
+          }
+        ],
+        indices: [
+          {
+            columnNames: ["guild_id"]
+          }
+        ],
+        foreignKeys: [
+          {
+            columnNames: ["command_message_id"],
+            referencedTableName: "messages",
+            referencedColumnNames: ["id"],
+            onDelete: "CASCADE"
+          },
+          {
+            columnNames: ["response_message_id"],
+            referencedTableName: "messages",
+            referencedColumnNames: ["id"],
+            onDelete: "CASCADE"
+          }
+        ]
+      })
+    );
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<any> {
+    await queryRunner.dropTable("tag_responses");
+  }
+}