type Group struct {
GroupID string `db:"group_id" pgddl:"TEXT NOT NULL" pk:"true"`
GroupName string `db:"group_name" pgddl:"TEXT NOT NULL"`
Description string `db:"description" pgddl:"TEXT NOT NULL"`
}
type User struct {
UserID string `db:"user_id" pgddl:"TEXT NOT NULL" pk:"true"`
Username string `db:"username" pgddl:"TEXT NOT NULL"`
Age int `db:"age" pgddl:"INT NOT NULL"`
}