Change Username Specification

templates/register.html

@@ -17,6 +17,7 @@
       <form action="/reg" method="POST">
         <ul>
           <li>Password must be at least 8 characters long.</li>
+          <li>Username must not contain any of the following characters: &.+?;</li>
           <li>Username may not contain offensive content.</li>
           <li>Your username cannot be changed later.</li>
         </ul>