20: printproduct group mutation (#21)

* Finished the mutation for productGroups

* Fixes after CR

* added enums for typeid

src/schema.graphql

@@ -402,5 +402,6 @@ type Mutation {
     productId: Int!
     markets: [ProductBlacklistingInput]
   ): Product
+  productGroup(productId: Int!, groupIds: [Int]): Product
   productKeywords(productId: Int!, keywordIds: [Int]): Product
 }