Add admin panel for users and votes

Closes #2

views/admin.erb

@@ -0,0 +1,29 @@
+<h1><%= _("Admin") %></h1>
+
+<h2><%= _("Users") %></h2>
+
+<ul>
+<% @users.reverse.each do |user| %>
+  <li>
+  <a href="/admin/users/<%= user.id %>"><%= user.email %></a>
+  </li>
+<% end %>
+</ul>
+
+<h2><%= _("Votes") %></h2>
+
+<ul>
+<% @votes.reverse.each do |vote| %>
+  <li>
+    <a href="/admin/votes/<%= vote.id %>"><%= vote.title %></a>
+    <% case vote.state
+       when 'draft' %>
+      <%= _("(Draft)") %>
+    <% when 'open' %>
+      <%= _("(Open)") %>
+    <% when 'closed' %>
+      <%= _("(Closed)") %>
+    <% end %>
+  </li>
+<% end %>
+</ul>