feat: introduce singleton webhook URL

packages/backend/src/db/migrations/20230609201228_add_webhook_path_in_step.ts

@@ -0,0 +1,13 @@
+import { Knex } from 'knex';
+
+export async function up(knex: Knex): Promise<void> {
+  return knex.schema.table('steps', (table) => {
+    table.string('webhook_path');
+  });
+}
+
+export async function down(knex: Knex): Promise<void> {
+  return knex.schema.table('steps', (table) => {
+    table.dropColumn('webhook_path');
+  });
+}

packages/backend/src/db/migrations/20230609201909_populate_data_in_webhook_path_in_step.ts

@@ -0,0 +1,16 @@
+import { Knex } from 'knex';
+
+export async function up(knex: Knex): Promise<void> {
+  return await knex('steps')
+    .where('type', 'trigger')
+    .whereIn('app_key', ['gitlab', 'typeform', 'twilio', 'flowers-software', 'webhook'])
+    .update({
+      webhook_path: knex.raw('? || ??', ['/webhooks/flows/', knex.ref('flow_id')]),
+    });
+}
+
+export async function down(knex: Knex): Promise<void> {
+  return await knex('steps').update({
+    webhook_path: null
+  });
+}