add-backend

**Shared instructions: [shared-instructions.md](../../shared/shared-instructions.md)** # Add an app backend **Required first:** pass the [Rayfin feature gate](../../shared/shared-instructions.md#rayfin-feature-gate). ## 1. Set up the database If `rayfin/rayfin.yml` exists, use the existing configuration. Otherwise, run: ```bash ms app add backend --provider rayfin --json ``` This creates the backend configuration, TypeScript configuration and `rayfin/data/`. Keep the existing app layout and exclude `rayfin/.temp/` from version control. This prepares the app's backend definitions; it does not provision a database. Rayfin is the app backend, not an existing database to select or connect to. ## 2. Install dependencies Run from the app root before continuing so the declared dependencies and their version-matched docs are available in `node_modules`: ```bash npm install ``` Use the app's existing package manager and lockfile if it does not use npm. Report installation or peer-dependency errors; do not force-install or downgrade the app to bypass them. Add missing direct dependencies only as required by the implementation described in the references. ## 3. Implement and check the app Read the installed package docs identified in these references, then follow them in order: - [Data modeling](./references/rayfin-data-modeling.md): entities, permissions and required [Managed Apps host initialization](./references/rayfin-data-modeling.md#step-4-initialize-through-managed-apps). - [CRUD UI](./references/rayfin-crud-ui.md): lists, forms, mutations and persistence checks. When invoked from `/create-app`, complete data modeling in Step 9 and return the entity/client paths; that workflow handles UI implementation and checks in Steps 10-11. Standalone use continues through both references. ## 4. Follow the app lifecycle Use the normal [app build and deploy workflow](../../shared/development-standards.md#build--deploy), not a separate Rayfin provisioning workflow.