docs: update contributing pages (#2503)

docs/docs/developer/database-migrations.md

@@ -0,0 +1,14 @@
+# Database Migrations
+
+After making any changes in the `server/libs/database/src/entities`, a database migration need to run in order to register the changes in the database. Follow the steps below to create a new migration.
+
+1. Run the command
+
+```bash
+npm run typeorm:migrations:generate ./libs/infra/src/<migration-name>
+```
+
+2. Check if the migration file makes sense.
+3. Move the migration file to folder `server/libs/database/src/migrations` in your code editor.
+
+The server will automatically detect `*.ts` file changes and restart. Part of the server start-up process includes running any new migrations, so it will be applied immediately.