Hi. I am going to the official Tutorial for upgradable SmartContracts using OpenZellin-OS and got in stuck very fast:
The base contract is importing zos-lib/contracts/migrations/Migratable.sol. But there is none in zos-lib.
pragma solidity ^0.4.21;
import "zos-lib/contracts/migrations/Migratable.sol";
contract MyContract is Migratable {
uint256 public x;
function initialize(uint256 _x) isInitializer("MyContract", "0") public {
x = _x;
}
}
The command zos add MyContract
gives the following error:
Could not find zos-lib/contracts/migrations/Migratable.sol from any sources
Looking into the sos-lib package, there is no migration-folder.
$ ls -l node_modules/zos-lib/contracts/
lists only those:
Initializable.sol
application
cryptography
ownership
upgradeability
util
Do I have to add more packages in order to make it work?