Merge pull request #3 from nfl/fix_missing_javadoc_for_comparator_war…

…ning

Fix missing javadoc for comparator warning

src/main/java/com/nfl/dm/shield/dynamic/domain/instance/OrderBy.java

@@ -24,6 +24,8 @@ public enum OrderBy {
 
     /**
      * Returns the comparator for the field (for in-memory sorting of the result set).
+     *
+     * @return a comparator by updateDate: nulls first, then earliest update dates, and eventually most recent update dates
      */
     public Comparator<SchemaInstance> getComparator() {
         return comparator;