Add message if a dummy person has been linked to user

aleksis/core/templates/core/no_person.html

@@ -7,13 +7,23 @@
     <div>
       <i class="material-icons left">error</i>
 
-      <p>
-        {% blocktrans %}
-          Your user account is not linked to a person. This means you
-          cannot access any school-related information. Please contact
-          the managers of AlekSIS at your school.
-        {% endblocktrans %}
-      </p>
+      {% if user.person.is_dummy %}
+        <p>
+          {% blocktrans %}
+            Your administrator account is not linked to any person. Therefore,
+            a dummy person has been linked to your account.
+          {% endblocktrans %}
+        </p>
+      {% else %}
+        <p>
+          {% blocktrans %}
+            Your user account is not linked to a person. This means you
+            cannot access any school-related information. Please contact
+            the managers of AlekSIS at your school.
+          {% endblocktrans %}
+        </p>
+      {% endif %}
+
     </div>
   </div>
 {% endif %}