implement update-single-nav-menu-item in nera package.

This function is so the user can add/remove a single page from the
nav. menu whilst editting the page.

src/nera.lisp

@@ -44,7 +44,8 @@
 	   #:update-archive-entry-property
 	   #:latest-archive-editted-entries
 	   #:latest-editted-pages
-	   #:latest-storage-editted-files))
+	   #:latest-storage-editted-files
+	   #:update-single-nav-menu-item))
 (in-package #:nera-db)
 
 (defparameter *tables* '(user site-settings page storage-file archive-entry)
@@ -248,6 +249,14 @@ editted article entry as the first item in the list.."
 		     (utils:checkbox-to-bool (cdr page)))
 	       (mito:save-dao page-to-update)))))
 
+(defun update-single-nav-menu-item (slug show-in-nav)
+  "Toggles a single page from the navigation menu."
+  (with-connection (db)
+    (let ((page-to-update (mito:find-dao 'page :slug slug)))
+      (setf (pages::enable-nav-menu-p page-to-update) show-in-nav)
+	    ;; (utils:checkbox-to-bool show-in-nav))
+      (mito:save-dao page-to-update))))
+
 (defun nav-menu-slugs ()
   (with-connection (db)
     (mito:select-dao 'page