def trade(currency_code, price, amount, action, limit = nil, counter_currency_code = "jpy")
            currency_pair = currency_code + "_" + counter_currency_code
            params = {:currency_pair => currency_pair, :action => action, :price => price, :amount => amount}
            params.store(:limit, limit) if limit
            json = post_ssl(@zaif_trade_url, "trade", params)
            return json
        end
def trade(currency_code, price, amount, action, limit = nil, counter_currency_code = "jpy")
            currency_pair = currency_code + "_" + counter_currency_code
            params = {:currency_pair => currency_pair, :action => action, :price => price, :amount => amount}
            params.store(:limit, limit) if limit
            json = post_ssl(@zaif_trade_url, "trade", params)
            return json
        end
Issue trade.
 Need api key.