fixed url; (bug 811091)

mkt/ecosystem/templates/ecosystem/base.html

@@ -15,7 +15,7 @@
         <ul class="c">
           <li>
             <a href="{{ url('ecosystem.documentation',
-                        page='principles') }}"
+                        page='purpose') }}"
                {% if category == 'design' %}class="selected"{% endif %}>
               {{ _('Design') }}
             </a>