show mailboxes that a catch-all alias belongs to

app/dashboard/templates/dashboard/domain_detail/info.html

@@ -29,7 +29,12 @@
     This feature allows you to create aliases <b>on the fly</b>.
     Simply use <em>anything@{{ custom_domain.domain }}</em>
     next time you need an email address. <br>
-    The alias will be created the first time it receives an email.
+    The alias will be created the first time it receives an email
+    and automatically belong to <b>{{ custom_domain.domain }}</b> mailboxes (
+    {% for mailbox in custom_domain.mailboxes %}
+      <b>{{ mailbox.email }}</b>
+      {% if not loop.last %},{% endif %}
+    {% endfor %})
   </div>
 
   <div>
@@ -67,7 +72,7 @@
                name="alias-name"
                placeholder="Alias name">
       </div>
-      <button class="btn btn-primary">Save</a>
+      <button class="btn btn-primary">Save</button>
     </form>
   </div>