Update show.html.erb

fix error when @entries.first is nil

app/views/admin/universal_tables/show.html.erb

@@ -27,7 +27,7 @@
       </tr>
     </thead>
     <tbody>
-    <% can_edit = can_edit_or_delete?(@entries.first.u_table) %> 
+    <% can_edit = can_edit_or_delete?(@entries.first.u_table) if !(@entries.first.nil?) %> 
     <% @entries.each do |entry| %>
       <tr>
       <% @columns.each_with_index do |column, index| %>