offline: toggleCollapseCat() update status in local db

feedlist.js

@@ -400,6 +400,8 @@ function toggleCollapseCat(cat) {
 		new Ajax.Request("backend.php?op=feeds&subop=collapse&cid=" + 
 			param_escape(cat));
 
+		local_collapse_cat(cat);
+
 	} catch (e) {
 		exception_error("toggleCollapseCat", e);
 	}

offline.js

@@ -830,3 +830,13 @@ function gotoOnline() {
 	window.location.href = "tt-rss.php";
 }
 
+function local_collapse_cat(id) {
+	try {
+		if (db) {
+			db.execute("UPDATE categories SET collapsed = NOT collapsed WHERE id = ?",
+				[id]);
+		}	
+	} catch (e) {
+		exception_error("local_collapse_cat", e);
+	}
+}