fix unmarshal bug with custom field name

the correct field was not found because of a wrong name check. Now it's always
compared with lowercased names.

Author: wwwdata

api_interfaces_test.go

@@ -105,8 +105,8 @@ var _ = Describe("Test interface api type casting", func() {
 		Expect(rec.Code).To(Equal(http.StatusOK))
 	})
 
-	It("reproduce issue with lowercase renaming", func() {
-		reqBody := strings.NewReader(`{"data": [{"attributes":{"customerId": 2 }, "type": "someDatas"}]}`)
+	It("Post works with lowercase renaming", func() {
+		reqBody := strings.NewReader(`{"data": [{"attributes":{"customerId": "2" }, "type": "someDatas"}]}`)
 		req, err := http.NewRequest("POST", "/v1/someDatas", reqBody)
 		Expect(err).To(BeNil())
 		api.Handler().ServeHTTP(rec, req)

jsonapi/unmarshal.go

@@ -260,7 +260,7 @@ func UnmarshalInto(input map[string]interface{}, targetStructType reflect.Type,
 						for x := 0; x < val.NumField(); x++ {
 							tfield := val.Type().Field(x)
 							name := GetTagValueByName(tfield, "name")
-							if name == strings.ToLower(fieldName) {
+							if strings.ToLower(name) == strings.ToLower(fieldName) {
 								field = val.Field(x)
 							}
 						}