most of add

categories/categories.go

@@ -48,6 +48,19 @@ func LoadCategories(db *sql.DB) {
 	}
 }
 
+func Add(db *sql.DB, name string, parent int) error {
+	var err error
+	if parent < 0 {
+		err := db.Exec("INSERT INTO categories (name) VALUE ($1)", name)
+	} else {
+		err := db.Exec("INSERT INTO categories (name, parent_id) VALUE ($1, $2)", name, parent)
+	}
+	if err != nil {
+		fmt.Println("Categories DB Error Add(): " , err)
+	}
+	return err
+}
+
 func (category *Category) ChangeParent(db *sql.DB, parent *Category) error {
     var err error 
     if parent == nil {