TERP-721

TERP-721 是一个与 cw721 兼容的规范，它添加了链上合约元数据，包括残值。

pub struct CollectionInfo<T> {
    pub creator: String,
    pub description: String,
    pub image: String,
    pub external_link: Option<String>,
    pub trading_start_time: Option<Timestamp>,
    pub residual_info: Option<T>,
}

pub struct ResidualInfo {
    pub payment_address: Addr,
    pub share: Decimal,
}

上述内容在合约实例化时设置。合约从 cw721-base 继承其他一切。