// First, deploying Relay, then deploying Donation and retrieve Donation contract address in 'donation_contract_address'

// Then, linking Relay to my first version of my contract Donation 
Relay.deployed().then(function(contractInstance) {
   contractInstance.changeContract(donation_contract_address);
})

// Then, I want to call sendDonation from the Donation contract
// !!!!! I DON'T KNOW WHAT IS THE CORRECT WAY TO CALL THIS !!!!!!
Relay.deployed().then(function(contractInstance) {
   contractInstance.sendDonation(5) ;
})
// OR 
Relay.deployed().then(function(contractInstance) {
   contractInstance.currentVersion.delegateCall(sendDonation(5)) ;
})

// Now I want to update the Donation contract to add the cancelDonation function
// First I deploy the new contract DonationNew and retrieve it's address in 'donation_new_contract_address'
Relay.deployed().then(function(contractInstance) {
   contractInstance.changeContract(donation_new_contract_address);
})

// are the state variables still available from the old contract to the new one?

// Then if I want to call the new function : 
Relay.deployed().then(function(contractInstance) {
   contractInstance.cancelDonation() ;
})