Added missing backtick quotes.

Thanks to xet7 !

models/boards.js

@@ -1263,12 +1263,12 @@ function boardRemover(userId, doc) {
 }
 
 Boards.uniqueTitle = title => {
-  const m = title.match(/^(?<title>.*?)\s*(\[(?<num>\d+)]\s*$|\s*$)/);
+  const m = title.match(`/^(?<title>.*?)\s*(\[(?<num>\d+)]\s*$|\s*$)/`);
   const base = escapeForRegex(m.groups.title);
   let num = 0;
   Boards.find({ title: new RegExp(`^${base}\\s*\\[\\d+]\\s*$`) }).forEach(
     board => {
-      const m = board.title.match(/^(?<title>.*?)\s*\[(?<num>\d+)]\s*$/);
+      const m = board.title.match(`/^(?<title>.*?)\s*\[(?<num>\d+)]\s*$/`);
       if (m) {
         const n = parseInt(m.groups.num, 10);
         num = num < n ? n : num;