use translation for title

Author: hagenburger

source/layouts/layout.erb

@@ -4,7 +4,7 @@
     <meta charset="utf-8">
     <meta content="IE=edge,chrome=1" http-equiv="X-UA-Compatible">
     <meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=1" name="viewport">
-    <title>Berlin Code of Conduct</title>
+    <title><%= t('header.title') %></title>
     <link href="stylesheets/style.css" rel="stylesheet">
     <script src="//use.typekit.net/vvs3qav.js"></script>
     <script>try{Typekit.load();}catch(e){}</script>