Graphite: added timeStack function definition, Closes #1118

src/app/services/graphite/gfunc.js

@@ -357,6 +357,17 @@ function (_) {
     defaultParams: ['1d']
   });
 
+  addFuncDef({
+    name: 'timeStack',
+    category: categories.Transform,
+    params: [
+      { name: "timeShiftUnit", type: "select", options: ['1h', '6h', '12h', '1d', '2d', '7d', '14d', '30d'] },
+      { name: "timeShiftStart", type: "int" },
+      { name: "timeShiftEnd", type: "int" }
+    ],
+    defaultParams: ['1d', 0, 7]
+  });
+
   addFuncDef({
     name: 'summarize',
     category: categories.Transform,