Add docs page on synchronization

docs/pages/docs/Examples/server_sync.md

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+---
+data:
+  title: "Backend synchronization"
+  description: Approaches for syncing drift databases between clients and backends.
+template: layouts/docs/single
+---
+
+At its core, drift is a package to access relational databases. On clients, that would
+typically be a SQLite3 database, which is what drift is optimized for.
+More recently, drift also gained stable support for [PostgreSQL databases]({{ '../Platforms/postgres.md' | pageUrl }}) as well.
+This allows drift to be deployed in [fullstack Dart applications](https://github.com/simolus3/drift/tree/develop/examples/multi_package),
+where a server uses drift to talk to a Postgres database and clients use it to manage a sqlite3 database.
+Thanks to utilities like [DialectAwareSqlType](https://pub.dev/documentation/drift/latest/drift/DialectAwareSqlType-class.html),
+it is also possible to share schema definitions between the two database systems.
+
+But regardless of whether the backend is using drift or not, synchronizing data between frontend and
+backend services can be complex.
+It is not something drift is set up to do automatically, but drift can integrate with existing solutions
+enabling synchronization.
+This page lists a few options and how they can be integrated into drift.
+If you have experience with alternatives that you can share, please feel free to open an issue or contribute
+to this page!
+
+## Manual
+
+One approach that requires more work to configure, but also gives you the most flexibility, is to write
+most of the synchronization logic yourself.
+
+For instance, synchronizing changes made locally in the app could be tracked in additional tables - perhaps
+with a `CREATE TRIGGER` statement keeping a log of changes made to database tables you want to sync.
+Periodically, a background job could then post this log of changes to your backend server.
+
+Dominik Roszkowski has given a [talk at Fluttercon 2023](https://www.droidcon.com/2023/08/06/from-network-failures-to-offline-success-a-journey-of-visible-app/)
+in which he shares the approach used by Visible to sync local changes to the server.
+Additional approaches are also discussed in [this issue](https://github.com/simolus3/drift/issues/136) and
+[here](https://github.com/simolus3/drift/discussions/2880).
+
+## ElectricSQL
+
+[ElectricSQL](https://electric-sql.com/) is a solution you can self-host to synchronize PostgreSQL databases
+with clients.
+Instead of having to deal with changes manually, a service receives updates from the PostgreSQL server and
+local sqlite3 databases. This service takes care of all the synchronization logic, with no backend changes
+and only simple frontend changes being required to integrate this.
+
+There is no official Dart support yet, but there are [community bindings](https://github.com/SkillDevs/electric_dart)
+which have great support for drift databases.
+This even works with stream queries - writes happening in the backend are quickly synchronized to the frontend,
+and will update the UI right away.
+
+[This example](https://github.com/SkillDevs/electric_dart/tree/master/todos_flutter) contains a Flutter app
+and a simple backend, both using drift and synchronizing their database with ElectricSQL.