Create dynamic dropdown menu with rails_versions

Author: toshimaru

src/_layouts/default.html

@@ -38,9 +38,11 @@
             v{{ page.version }}
           </a>
           <div class="dropdown-menu dropdown-menu-md-right" aria-labelledby="dropdownMenuLink">
-            <a class="dropdown-item" href="/">v6.1</a>
-            <a class="dropdown-item" href="/6.0/">v6.0</a>
-            <a class="dropdown-item" href="/5.2/">v5.2</a>
+            <a class="dropdown-item" href="/">v7.0</a>
+            {% for rails_version in site.rails_versions %}
+              {% assign version = rails_version.first %}
+              <a class="dropdown-item" href="/{{ version }}/">v{{ version }}</a>
+            {% endfor %}
           </div>
         </div>
       </li>