ErrInvalidRequest returns a structured http response for invalid requests.

ErrNotFound returns a structured http response if a resource couln't be found.

ErrRender returns a structured http response in case of rendering errors.

Article is one instance of an article.

ArticleList contains a list of articles.

ErrResponse renderer type for handling all sorts of errors.

Order is one instance of an order.

OrderList contains a list of orders.