add database section to book

book/src/SUMMARY.md

@@ -9,6 +9,7 @@
   - [DNS](proxy/dns.md)
   - [HTTPS](proxy/https.md)
 - [Services](services.md)
+- [Database](database.md)
 - [Federation](federation.md)
 - [Haze scripts](scripts.md)
 - [Xdebug](xdebug.md)

book/src/database.md

@@ -0,0 +1,33 @@
+# Database
+
+There are 3 ways of accessing the database of a haze instance.
+
+## CLI
+
+```bash
+haze [filter] db [query]
+```
+
+Opens the command line client for the database. If a query is specified, it will
+be executed. If no query is specified, an interactive shell will be started.
+
+Example
+
+```
+haze db 'select fileid, storage, path from oc_filecache'
+```
+
+## WebUI
+
+A web UI (based on [DbGate](https://www.dbgate.io/)) is available with every
+instance.
+
+It can be accessed by using `haze open db`, or, if the proxy is setup at
+`db.haze.example.com`.
+
+## External tools
+
+For usage with external tools, the database connection URL is printed when the
+instance is created.
+
+Details on how to use the connection URL is dependent on the external tool.