diff --git a/install.rst b/install.rst
index 64bd48885..aab99d31a 100644
--- a/install.rst
+++ b/install.rst
@@ -98,6 +98,8 @@ db-uri
 
   On older systems like Centos 6, with older versions of libpq, a different db-uri syntax has to be used. In this case the URI is a string of space separated key-value pairs (key=value), so the example above would be :code:`"host=host user=user port=5432 dbname=dbname password=pass"`.
 
+  Choosing a value for this parameter beginning with the at sign such as ``@filename`` (e.g. ``@./configs/my-config``) loads the secret out of an external file.
+
 .. _db-schema:
 
 db-schema