diff --git a/.github/workflows/sonar.yml b/.github/workflows/sonar.yml
index f5a2689..7392e68 100644
--- a/.github/workflows/sonar.yml
+++ b/.github/workflows/sonar.yml
@@ -28,6 +28,8 @@ jobs:
 
       - name: Generate Prisma client
         run: npm run prisma:generate
+        env:
+          DATABASE_URL: "file:./dev.db"
 
       - name: Run Angular tests with coverage
         run: npm test -- --code-coverage --watch=false --browsers=ChromeHeadless
diff --git a/COLLABORATION.md b/COLLABORATION.md
new file mode 100644
index 0000000..57b71a6
--- /dev/null
+++ b/COLLABORATION.md
@@ -0,0 +1,177 @@
+# Collaboration in OpenTimeTracker
+
+Brief guide to contribute consistently. English first, Spanish version below.
+
+## Summary
+
+- Stack: Angular 21 + Electron 37 + Prisma/SQLite.
+- Default branch: main. Working branch: develop (use develop-to-main in this session if needed).
+- License: GPL-3.0.
+
+## Getting Ready
+
+1. Requirements: Node 20+, npm 10+, Docker + Docker Compose (for SonarQube).
+2. Install deps:
+
+   ```bash
+   npm install
+   npm run prisma:generate
+   ```
+
+3. Run the app:
+
+   ```bash
+   npm start            # Angular dev server on 4200
+   npm run dev          # build + Electron dev mode
+   ```
+
+## Workflow
+
+- Branch from develop with prefixes `feat/`, `fix/`, `chore/`.
+- Conventional Commits (commitlint enforced).
+- Before opening a PR:
+
+  ```bash
+  npm run lint
+  npm test
+  npm run test:electron
+  npm run sonar:check   # tests + coverage + SonarQube
+  ```
+
+- In the PR: goal, key changes, DB/backup impact, UI screenshots if any, test steps.
+- Flag breaking changes and link issues.
+
+## Quality and SonarQube
+
+- Pre-push hook runs `sonar:check`; failures block the push.
+- Quick local Sonar:
+
+  ```bash
+  docker-compose up -d      # first start ~2min
+  # create SONAR_TOKEN at http://localhost:9000
+  echo "SONAR_TOKEN=..." > .env
+  npm run sonar:check
+  docker-compose down
+  ```
+
+## Database
+
+- Prisma with local SQLite. For schema changes:
+
+  ```bash
+  npx prisma migrate dev --name description
+  npm run prisma:template   # update production template.db
+  ```
+
+- Do not commit real data to backups or seeds. Review prisma/template.db and migrations.
+
+## UI and i18n
+
+- Uses PrimeNG/PrimeFlex, dark theme by default.
+- Add strings in src/assets/i18n/en.json and src/assets/i18n/es.json.
+- Mind accessibility: labels, visible focus, contrast.
+
+## Security and Secrets
+
+- Do not commit .env or tokens. Keep secrets local.
+
+## Issues and Support
+
+- For issues/PRs include: repro steps, expected/actual, relevant logs, version (commit/branch), platform.
+
+## Resources
+
+- Overview and shortcuts: README.md.
+- Commands and scripts: package.json.
+
+Happy hacking 🚀
+
+---
+
+## Colaboración en OpenTimeTracker (Español)
+
+Guía breve para contribuir de forma consistente.
+
+### Resumen
+
+- Stack: Angular 21 + Electron 37 + Prisma/SQLite.
+- Rama por defecto: main. Rama de trabajo habitual: develop (usa develop-to-main en esta sesión si aplica).
+- Licencia: GPL-3.0.
+
+### Preparación
+
+1. Requisitos: Node 20+, npm 10+, Docker + Docker Compose (para SonarQube).
+2. Instala dependencias:
+
+   ```bash
+   npm install
+   npm run prisma:generate
+   ```
+
+3. Ejecuta la app:
+
+   ```bash
+   npm start            # servidor Angular en 4200
+   npm run dev          # build + Electron en modo desarrollo
+   ```
+
+### Flujo de trabajo
+
+- Crea ramas desde develop con prefijos `feat/`, `fix/`, `chore/`.
+- Commits con Conventional Commits (commitlint activo).
+- Antes de abrir PR:
+
+  ```bash
+  npm run lint
+  npm test
+  npm run test:electron
+  npm run sonar:check   # corre tests + cobertura + SonarQube
+  ```
+
+- Incluye en el PR: objetivo, cambios clave, impacto en DB/backup, capturas si hay UI, pasos de prueba.
+- Marca breaking changes y enlaza issues.
+
+### Calidad y SonarQube
+
+- Hook pre-push ejecuta `sonar:check`; fallos bloquean el push.
+- Sonar local rápido:
+
+  ```bash
+  docker-compose up -d      # primer arranque puede tardar ~2min
+  # generar SONAR_TOKEN en http://localhost:9000
+  echo "SONAR_TOKEN=..." > .env
+  npm run sonar:check
+  docker-compose down
+  ```
+
+### Base de datos
+
+- Prisma con SQLite local. Para cambios de modelo:
+
+  ```bash
+  npx prisma migrate dev --name descripcion
+  npm run prisma:template   # actualiza template.db de producción
+  ```
+
+- No subas datos reales a backups ni seeds. Revisa cambios en prisma/template.db y migrations.
+
+### UI e i18n
+
+- Componentes con PrimeNG/PrimeFlex, tema oscuro por defecto.
+- Añade cadenas en src/assets/i18n/en.json y src/assets/i18n/es.json.
+- Cuida accesibilidad: labels, focus visible, contrastes.
+
+### Seguridad y secretos
+
+- No commitees .env ni tokens. Usa variables locales.
+
+### Issues y soporte
+
+- Al crear un issue o PR, incluye: pasos reproducibles, resultado esperado/obtenido, logs relevantes, versión (commit/branch), plataforma.
+
+### Recursos
+
+- Vista general y atajos: README.md.
+- Comandos y scripts: package.json.
+
+Happy hacking 🚀