Fixes mm-1991 Allow ability to white label

web/templates/signup_team.html

@@ -9,7 +9,7 @@
                 <div class="col-sm-12">
                     <div class="signup-team__container">
                         <img class="signup-team-logo" src="/static/images/logo.png" />
-                        <h1>Mattermost</h1>
+                        <h1>{{ .SiteName }}</h1>
                         <h4 class="color--light">All team communication in one place, searchable and accessible anywhere</h4>
                         <div id="signup-team"></div>
                     </div>