Add proposals index in admin

app/views/admin/proposals/index.html.erb

@@ -0,0 +1,37 @@
+<% provide(:title) do %>
+  <%= t("admin.header.title") %> - <%= t("admin.proposals.index.title") %>
+<% end %>
+
+<h2><%= t("admin.proposals.index.title") %></h2>
+
+<% if @proposals.any? %>
+  <h3><%= page_entries_info @proposals %></h3>
+
+  <table>
+    <thead>
+      <tr>
+        <th class="text-center"><%= t("admin.proposals.index.id") %></th>
+        <th><%= t("admin.proposals.index.title") %></th>
+        <th><%= t("admin.proposals.index.author") %></th>
+        <th><%= t("admin.proposals.index.milestones") %></th>
+      </tr>
+    </thead>
+
+    <tbody>
+      <% @proposals.each do |proposal| %>
+        <tr id="<%= dom_id(proposal) %>" class="proposal">
+          <td class="text-center"><%= proposal.id %></td>
+          <td><%= link_to proposal.title, admin_proposal_path(proposal) %></td>
+          <td><%= proposal.author.username %></td>
+          <td><%= proposal.milestones.count %></td>
+        </tr>
+      <% end %>
+    </tbody>
+  </table>
+
+  <%= paginate @proposals %>
+<% else %>
+  <div class="callout primary">
+    <%= t("admin.proposals.index.no_proposals") %>
+  </div>
+<% end %>