Seeking ERC20-Token/Crowdsale examples

Hi @oxuw4

Upgradability is hugely important consideration when developing smart contracts.

As you have looked at Centre, suggest starting with their article on Designing an upgradeable Ethereum contract and how they came to use ZeppelinOS Proxy patterns

To learn more about ZeppelinOS I suggest the following tutorials:

The ZeppelinOS documentation has easy to follow tutorials on deploying and then upgrading a smart contract.
(Please note, use versions truffle@5.0.2 and ganache-cli@6.3.0. Also when starting the zos session, use your second ganache account as the from)

@paulinablaszk wrote a great tutorial on upgrading to fix a vulnerability

@ylv-io wrote a tutorial on solidity hot reloading using ZepKit. Hot reloading is amazing to see in action.

Let us know if you have more questions or any issues running the tutorials (I have run through all of the above tutorials and found them really helpful)