added synapsesToMap to maps/_new.html.erb so they can be passed to maps controller

app/views/maps/_new.html.erb

@@ -8,6 +8,7 @@
   <label for="map_permission">Permission</label>
   <%= form.select(:permission, options_for_select(['commons', 'public', 'private'])) %>
   <%= form.hidden_field :topicsToMap, :value => 0 %>
+  <%= form.hidden_field :synapsesToMap, :value => 0 %>
   <%= form.submit "Save", class: "add" %>
   <button onclick="$('#new_map').fadeOut('fast'); event.preventDefault();">Cancel</button>
   <div class="clearfloat"></div>