[DOP-25282] Add frontend docs

Author: dolfinus

docs/index.rst

@@ -18,6 +18,7 @@
     reference/database/index
     reference/broker/index
     reference/server/index
+    reference/frontend/index
     reference/worker/index
     reference/scheduler/index
 

docs/reference/frontend/configuration.rst

@@ -0,0 +1,24 @@
+.. _configuration-frontend:
+
+Frontend configuration
+======================
+
+API url
+-------
+
+SyncMaster UI requires REST API to be accessible from browser. API url is set up using environment variable:
+
+.. code:: bash
+
+    SYNCMASTER__UI__API_BROWSER_URL=http://localhost:8000
+
+If both REST API and frontend are served on the same domain (e.g. through Nginx reverse proxy), for example:
+
+- REST API → ``/api``
+- Frontend → ``/``
+
+Then you can use relative path:
+
+.. code:: bash
+
+    SYNCMASTER__UI__API_BROWSER_URL=/api

docs/reference/frontend/index.rst

@@ -0,0 +1,46 @@
+.. _frontend:
+
+Frontend
+========
+
+SyncMaster provides a `Frontend (UI) <https://github.com/MobileTeleSystems/syncmaster-ui>`_ based on `React <https://react.dev/>`_,
+providing users the ability to create, update, delete entitities.
+
+Install & run
+-------------
+
+With Docker
+~~~~~~~~~~~
+
+* Install `Docker <https://docs.docker.com/engine/install/>`_
+* Install `docker-compose <https://github.com/docker/compose/releases/>`_
+
+* Run the following command:
+
+  .. code:: console
+
+    $ docker compose --profile frontend up -d --wait
+
+  ``docker-compose`` will download SyncMaster UI image, create containers, and then start them.
+
+  Options can be set via ``.env`` file or ``environment`` section in ``docker-compose.yml``
+
+  .. dropdown:: ``docker-compose.yml``
+
+      .. literalinclude:: ../../../docker-compose.yml
+          :emphasize-lines: 123-140
+
+  .. dropdown:: ``.env.docker``
+
+      .. literalinclude:: ../../../.env.docker
+          :emphasize-lines: 49-50
+
+* After frontend is started and ready, open http://localhost:3000.
+
+See also
+--------
+
+.. toctree::
+    :maxdepth: 1
+
+    configuration