added web monetization tag

Author: rochisha0

themes/vocabulary_theme/templates/layout.html

@@ -29,6 +29,7 @@
 {% endif %}
 <meta name="twitter:site" content="@creativecommons">
 <meta name="twitter:creator" content="@creativecommons">
+<meta name="monetization" content="$ilp.uphold.com/edR8erBDbRyq">
 <script src="https://code.jquery.com/jquery-3.3.1.min.js"
   integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
 <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.6/umd/popper.min.js"