fixed exercise show view

Author: marcelja

app/views/exercises/show.html.erb

@@ -12,14 +12,14 @@
   <dt><%= 'Visibility' %>:</dt>
   <dd><%= @exercise.public ? 'public' : 'private' %></dd>
   <dt><%= 'Created by' %>:</dt>
-  <% if defined? @exercise.user %>
+  <% if @exercise.user %>
     <% if @exercise.user.first_name.nil?%>
       <dd><%= "User#{@exercise.user.id}"%></dd>
     <% else %>
-        <dd><%= @exercise.user.name %></dd>
+      <dd><%= @exercise.user.name %></dd>
     <% end %>
   <% else %>
-    <%= 'User undefined' %>
+    <dd><%= 'User undefined' %></dd>
   <% end %>
   <dt><%= 'Created at' %>:</dt>
   <dd><%= @exercise.created_at %></dd>