Prepare to migrate usernames to a new table

src/migrations/1556908589679-CreateUsernameHistoryTable.ts

@@ -0,0 +1,46 @@
+import { MigrationInterface, QueryRunner, Table } from "typeorm";
+
+export class CreateUsernameHistoryTable1556908589679 implements MigrationInterface {
+  public async up(queryRunner: QueryRunner): Promise<any> {
+    await queryRunner.createTable(
+      new Table({
+        name: "username_history",
+        columns: [
+          {
+            name: "id",
+            type: "int",
+            unsigned: true,
+            isGenerated: true,
+            generationStrategy: "increment",
+            isPrimary: true,
+          },
+          {
+            name: "user_id",
+            type: "bigint",
+            unsigned: true,
+          },
+          {
+            name: "username",
+            type: "varchar",
+            length: "160",
+            isNullable: true,
+          },
+          {
+            name: "timestamp",
+            type: "datetime",
+            default: "CURRENT_TIMESTAMP",
+          },
+        ],
+        indices: [
+          {
+            columnNames: ["user_id"],
+          },
+        ],
+      }),
+    );
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<any> {
+    await queryRunner.dropTable("username_history", true);
+  }
+}