search credential files in Kalamars home directory

Change-Id: I47290300955f84294efdbeb9923b637658b1dcbe
diff --git a/kalamar.ids-mannheim.conf b/kalamar.ids-mannheim.conf
index 1173fb1..461f2f4 100644
--- a/kalamar.ids-mannheim.conf
+++ b/kalamar.ids-mannheim.conf
@@ -1,4 +1,3 @@
-use Mojo::File 'path';
 use Mojo::ByteStream 'b';
 
 $main::ENV{MOJO_MAX_LINE_SIZE} = 65536;
@@ -9,8 +8,8 @@
     engine => 'Kalamar::API'
   },
   'Kalamar-Auth' => {
-    client_id => b(path('.client_id')->slurp)->trim,
-    client_secret => b(path('.client_secret')->slurp)->trim,
+    client_id => b($app->home->child('.client_id')->slurp)->trim,
+    client_secret => b($app->home->child('.client_secret')->slurp)->trim,
     oauth2 => 1,
     experimental_client_registration => 1
   },