better signup disable

documentation/docs/Configuration/disable_registration.md

@@ -0,0 +1,12 @@
+---
+sidebar_position: 1
+---
+
+# Disable Registration
+
+To disable registration, you can set the following variable in your docker-compose.yml under the server service:
+
+```yaml
+environment:
+  - DISABLE_REGISTRATION=True
+```