GRN2-140: Added Email to inform user they've been promoted (#534)

* Added Email to inform user they've been promoted

* Update user_mailer.rb

* Send email when a user is demoted

* Change more-info string

app/views/user_mailer/user_demoted.html.erb

@@ -0,0 +1,39 @@
+<%
+# BigBlueButton open source conferencing system - http://www.bigbluebutton.org/.
+#
+# Copyright (c) 2018 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 style="text-align:center; font-family:'Source Sans Pro', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif">
+  <div style="display:inline-block; background-color:#F5F7FB; border:1px solid #d3d3d3; padding: 25px 70px; width: 50%">
+    <%= image_tag(@image, height: '70') %>
+
+    <h1 style="margin-bottom:30px">
+      <%= t('mailer.user.demoted.subtitle') %>
+    </h1>
+
+    <p>
+      <%= t('mailer.user.demoted.info', url: @url) %>
+    </p>
+
+    <p style="margin-bottom:45px;">
+      <%= t('mailer.user.demoted.more-info') %>
+    </p>
+
+    <a style="background: <%= @color %>;color: #ffffff; padding: 10px 15px; box-shadow: 0 2px 4px 0 rgba(0,0,0,.25);border: 1px solid transparent;text-decoration:none;" href="<%= @root_url %>">
+      <%= t('mailer.user.demoted.root_link') %>
+    </a>
+  </div>
+</div>