[Feature] Identify Missing Rules (#177)

Fixes #97
Co-authored-by: Tim Lorsbach <tim@lorsba.ch>
Reviewed-on: enviPath/enviPy#177

templates/actions/objects/pathway.html

@@ -22,6 +22,10 @@
             <i class="glyphicon glyphicon-floppy-save"></i> Download Pathway as Image</a>
     </li>
 {% if meta.can_edit %}
+    <li>
+        <a class="button" data-toggle="modal" data-target="#identify_missing_rules_modal">
+            <i class="glyphicon glyphicon-question-sign"></i> Identify Missing Rules</a>
+    </li>
     <li role="separator" class="divider"></li>
     <li>
         <a class="button" data-toggle="modal" data-target="#edit_pathway_modal">