Support for users and authentication [backend].

src/errors.ts

@@ -0,0 +1,20 @@
+abstract class ApplicationError extends Error {
+  constructor(public message: string) {
+    super(message);
+  }
+}
+
+class BadRequest extends ApplicationError { }
+class ValidationError extends BadRequest { }
+class Unauthorized extends BadRequest { }
+class Forbidden extends BadRequest { }
+class NotFound extends BadRequest { }
+
+export {
+  ApplicationError,
+  BadRequest,
+  Forbidden,
+  NotFound,
+  Unauthorized,
+  ValidationError,
+};