add guest landing page when guest access disabled

app/views/landing/guest.html.erb

@@ -0,0 +1,44 @@
+<%
+# BigBlueButton open source conferencing system - http://www.bigbluebutton.org/.
+# Copyright (c) 2016 BigBlueButton Inc. and by respective authors (see below).
+# This program is free software; you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free Software
+# Foundation; either version 3.0 of the License, or (at your option) any later
+# version.
+#
+# BigBlueButton is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+# You should have received a copy of the GNU Lesser General Public License along
+# with BigBlueButton; if not, see <http://www.gnu.org/licenses/>.
+%>
+
+<div class="page-wrapper meetings">
+  <div class="container-fluid">
+
+    <div class="center-panel-wrapper">
+        <%= render layout: 'shared/center_panel' do %>
+          <h1 class='text-center'><%= t('welcome_to_greenlight') %></h1>
+          <br>
+          <%= link_to user_login_path, class: "signin-link" do %>
+            <div class="signin-button center-block">
+              <div class="signin-icon-wrapper">
+                <%= image_tag("signin-icon.png", alt: "L", class: "signin-icon") %>
+              </div>
+              <div class="signin-text-wrapper text-center">
+                <span class="signin-text"><%= t('login_greenlight') %></span>
+              </div>
+            </div>
+          <% end %>
+          <br>
+          <p class='text-center' style='font-size: 13px;'> <%= t('guest_sentence_one_html', bbb_link: link_to('BigBlueButton',
+           'http://bigbluebutton.org/', target: "_blank")) %><br><%= t('guest_sentence_two') %></p>
+        <% end %>
+      </div>
+
+    <div class="text-center" style="padding-top:20px;">
+      <iframe width="560" height="315" src="https://www.youtube.com/embed/yGX3JCv7OVM" frameborder="0" allowfullscreen></iframe>
+    </div>
+
+  </div>
+</div>