Added username field for argon2copyparty only

templates/index.html

@@ -32,6 +32,8 @@
         </div>
         <div class="note">Salt characters limited to <code>./0-9A-Za-z</code>.</div>
 
+        <label for="username">Username (copyparty only)</label>
+        <input id="username" type="text" placeholder="Enter username">
 
         <div class="controls">
             <button id="hashBtn">Compute hash</button>