Update auth.rst (#672)

diff --git a/src/config/auth.rst b/src/config/auth.rst
index 39cfb73..70ec276 100644
--- a/src/config/auth.rst
+++ b/src/config/auth.rst
@@ -34,9 +34,10 @@
     ``_users`` database, but in the last ``[admins]`` section that CouchDB
     finds when loading its ini files. See :config:intro for details on config
     file order and behaviour. This file (which could be something like
-    ``etc/local.ini`` or ``etc/local.d/10-admins.ini`` on a Debian/Ubuntu
-    system installed from packages) should be appropriately secured and
-    readable only by system administrators::
+    ``/opt/couchdb/etc/local.ini`` or
+    ``/opt/couchdb/etc/local.d/10-admins.ini`` when CouchDB is installed from
+    packages) should be appropriately secured and     readable only by system
+    administrators::
 
         [admins]
         ;admin = mysecretpassword