Update commented use cases

lib/cartodb/models/dataview/histogram.js

@@ -176,13 +176,23 @@ var dateHistogramQueryTpl = dot.template([
 var TYPE = 'histogram';
 
 /**
- {
-     type: 'histogram',
-     options: {
-         column: 'name',
-         bins: 10, // OPTIONAL
-         aggregation: 'day' // OPTIONAL
-     }
+Numeric histogram:
+{
+    type: 'histogram',
+    options: {
+        column: 'name', // column data type: numeric
+        bins: 10 // OPTIONAL
+    }
+}
+
+Time series:
+{
+    type: 'histogram',
+    options: {
+        column: 'date', // column data type: date
+        aggregation: 'day' // OPTIONAL (if undefined then it'll be built as numeric)
+        timezone: -7200 // OPTIONAL (UTC offset in seconds)
+    }
  }
  */
 function Histogram(query, options, queries) {