Add put task endpoint (#33)

Closes #23

Reviewed-on: #33

backend/dto.go

@@ -36,14 +36,12 @@ type CreateGoalResponse struct {
 	ID int `json:"id"`
 }
 
-// CreateTaskRequest represents the request body for creating a new task.
 type CreateTaskRequest struct {
 	Name     string `json:"name" binding:"required"`
 	Reward   int    `json:"reward"`
 	Assigned *int   `json:"assigned"`
 }
 
-// CreateTaskResponse represents the response body after creating a new task.
 type CreateTaskResponse struct {
 	ID int `json:"id"`
 }