Add an example script on how to upgrade a contract implementation

scripts/upgrade-example.js

@@ -0,0 +1,16 @@
+const { ethers, upgrades } = require("hardhat");
+const Kredits = require('../lib/kredits');
+
+async function main() {
+  const network = await hre.ethers.provider.getNetwork();
+  kredits = new Kredits(hre.ethers.provider, hre.ethers.provider.getSigner());
+  await kredits.init();
+
+  const ContributorV2 = await ethers.getContractFactory("Contributor");
+  const contributor = await upgrades.upgradeProxy(kredits.Contributor.address, ContributorV2);
+  console.log("Contributor upgraded");
+
+  console.log("DONE!");
+}
+
+main();