initial commit (migrated)

lib/core/error/exception.dart

@@ -0,0 +1,16 @@
+/// Exception class for server error
+/// Generally, this exception is thrown when the server returns an error response
+class ServerException implements Exception {
+  const ServerException(this.message);
+
+  final String message;
+}
+
+/// Exception class for unauthorized client error
+/// this exception is thrown when the client is not authorized
+/// to access the resource (server returns 401)
+class UnauthorizedException implements Exception {
+  const UnauthorizedException(this.message);
+
+  final String message;
+}