add results service

internal/results/domain/errors.go

@@ -0,0 +1,11 @@
+package domain
+
+import "errors"
+
+var (
+	ErrResultNotFound      = errors.New("result not found")
+	ErrInvalidResultData   = errors.New("invalid result data")
+	ErrDuplicateResult     = errors.New("duplicate result")
+	ErrCompetitionNotFound = errors.New("competition not found")
+	ErrUserNotFound        = errors.New("user not found")
+)