feat: login service and implement database storage

internal/utilities/response/error_code.go

@@ -0,0 +1,15 @@
+package response
+
+import "net/http"
+
+type ErrorCode struct {
+	Code     string
+	Message  string
+	HttpCode int
+}
+
+var (
+	// 4xx
+	ErrBadRequest = ErrorCode{Code: "BAD_REQUEST", Message: "BAD_REQUEST", HttpCode: http.StatusBadRequest}
+	ErrDBRequest  = ErrorCode{Code: "BAD_DB_REQUEST", Message: "DB_ERROR", HttpCode: http.StatusBadRequest}
+)