REFS DEVOPS-234 Corrected syntax and/add

lib/pipeline/expressions/AddExpression.js

@@ -39,4 +39,4 @@ proto.evaluateInternal = function evaluateInternal(doc) {
 
 
 /** Register Expression */
-Expression.registerExpression("$and",AddExpression.parse);
+Expression.registerExpression("$add",AddExpression.parse);