fix counter eval

lib/orbit_app/module/visitor_counter_eval.rb

@@ -7,7 +7,7 @@ module OrbitApp
             map = "function(){ emit( this.referrer,{session_hash: this.session_hash,created_at: this.created_at}); };"
             reduce = "function(key, values){ var sum = 0; values.forEach(function(doc){sum += doc.amount; }); return {amount: sum};};"
             if options.blank?
-              impressions = Impression.count #collection.map_reduce(map, reduce,read: :primary, out: "vr")
+              impressions = Impression.collection.map_reduce(map, reduce,read: :primary, out: "vr")
             else
               query = Impression.where(options).selector
               impressions = Impression.where(options).collection.map_reduce(map, reduce,read: :primary, out: "vr",:query=>query)