1774 extensibility v1 create an exhaustive documentation readme or dedicated section in twenty contributing doc (#16751)

As title

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packages/twenty-server/src/database/typeorm/core/migrations/common/1766077618558-removeCanBeAssignedToApplications.ts

@@ -0,0 +1,19 @@
+import { type MigrationInterface, type QueryRunner } from 'typeorm';
+
+export class RemoveCanBeAssignedToApplications1766077618558
+  implements MigrationInterface
+{
+  name = 'RemoveCanBeAssignedToApplications1766077618558';
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `ALTER TABLE "core"."role" DROP COLUMN "canBeAssignedToApplications"`,
+    );
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `ALTER TABLE "core"."role" ADD "canBeAssignedToApplications" boolean NOT NULL DEFAULT true`,
+    );
+  }
+}