Add POST /user/{userId}/goals (#26)

Closes #4

Reviewed-on: #26

backend/dto.go

@@ -24,3 +24,13 @@ type Goal struct {
 	Progress int    `json:"progress"`
 	Weight   int    `json:"weight"`
 }
+
+type CreateGoalRequest struct {
+	Name   string `json:"name"`
+	Target int    `json:"target"`
+	Weight int    `json:"weight"`
+}
+
+type CreateGoalResponse struct {
+	ID int `json:"id"`
+}