Support the ability for admins to delete users

app/views/admin/users/show.html.haml

@@ -12,8 +12,10 @@
       .tab-content
         #user-info-content.tab-pane{class: "#{'active' unless params[:tab] == 'submissions-content'}"}
           - if can? :edit, @user
-            .pull-right
+            .pull-right.btn-group
               = link_to 'Edit', edit_admin_user_path(@user), class: 'btn btn-primary'
+              = link_to 'Delete', admin_user_path(@user),method: :delete, class: 'btn btn-danger',
+                data: {confirm: "Are you sure?"}
           %table.table
             - @show_attributes.each do |attr|
               %tr