feat: allow configuration of ropsten and ganache with env variables

migrations/2_deploy_contracts.js

@@ -1,5 +1,9 @@
 //var Ownable = artifacts.require("ownership/Ownable.sol");
 
+// NOTE: Use this file to easily deploy the contracts you're writing.
+//   (but make sure to reset this file before committing
+//    with `git checkout HEAD -- migrations/2_deploy_contracts.js`)
+
 module.exports = function(deployer) {
   //deployer.deploy(Ownable);
 };