setup user/auth repository and service

internal/exception/exception.go

@@ -0,0 +1,15 @@
+package exception
+
+import "fmt"
+
+type Exception struct {
+	Operation string
+}
+
+func New(operation string) *Exception {
+	return &Exception{Operation: operation}
+}
+
+func (e *Exception) WithError(err error) error {
+	return fmt.Errorf("%s: %w", e.Operation, err)
+}