starting to work on GroupBy aggregations

backend/pkg/models/query_resource.go

@@ -1,9 +1,22 @@
 package models
 
+type QueryResourceAggregationType string
+
+const (
+	QueryResourceAggregationTypeCountBy QueryResourceAggregationType = "countBy"
+	QueryResourceAggregationTypeGroupBy QueryResourceAggregationType = "groupBy"
+	QueryResourceAggregationTypeMinBy   QueryResourceAggregationType = "minBy"
+	QueryResourceAggregationTypeMaxBy   QueryResourceAggregationType = "maxBy"
+)
+
 // maps to frontend/src/app/models/widget/dashboard-widget-query.ts
 type QueryResource struct {
 	Use    string                 `json:"use"`
 	Select []string               `json:"select"`
 	From   string                 `json:"from"`
 	Where  map[string]interface{} `json:"where"`
+
+	//aggregation fields
+	AggregationParams []string                      `json:"aggregation_params"`
+	AggregationType   *QueryResourceAggregationType `json:"aggregation_type"`
 }

frontend/src/app/models/widget/dashboard-widget-query.ts

@@ -8,5 +8,5 @@ export class DashboardWidgetQuery {
 
   //https://lodash.com/docs/4.17.15#unionBy
   aggregation_params?: string[]
-  aggregation_type?: 'countBy' | 'unionBy' | 'groupBy' | 'orderBy' | 'sortBy' | 'minBy' | 'maxBy' | 'sumBy'
+  aggregation_type?: 'countBy' | 'groupBy' // | 'minBy' | 'maxBy' | 'sumBy' // 'orderBy' | 'sortBy' |
 }