In our exchange, we'll allow the user to buy or sell the gold asset using US dollars. Thus, gold will be our counter asset, that is, the asset that is being bought or sold. US dollars will be our base asset, that is, the asset that is being used to buy or sell.
Before we can build a trading exchange around these assets, we need to create these assets on our blockchain. To do so, we'll create an ERC20 token that represents gold, and an ERC20 token that represents USD. The tokens are fungible and fixed in nature, and can go up to two decimal places. One gold token represents one gram of gold, and one USD token represents one dollar.
