[docs] 📝 add guide to verify contracts source code

.doc/development-guide.md

@@ -0,0 +1,44 @@
+# Development Guide
+
+
+## Verify source code of deployed Contracts
+
+1. Create an account in polygonscan.com
+2. Create un API Key in your Polygon's account
+3. Copy your API Key from Polygonscan
+4. Create a .env file with the API Key
+
+```sh
+POLYGON_MUMBAI_RPC_PROVIDER = 'RPC Node URL'
+PRIVATE_KEY = 'your wallet private key'
+POLYGONSCAN_API_KEY = 'your polygonscan api key'
+```
+
+5. Install hardhat-etherscan dependency
+
+
+```sh
+npm install --save-dev @nomiclabs/hardhat-etherscan
+or 
+yarn add --dev @nomiclabs/hardhat-etherscan
+```
+
+6. Update your hardhat.config.js with etherscan
+
+
+```sh
+module.exports = {
+        solidity: ...
+        defaultNetwork: ...
+        networks: { ...}
+        etherscan: {
+           apiKey: POLYGONSCAN_API_KEY
+        }
+}
+```
+
+7. Verify the deployed contract address
+
+```sh
+npx hardhat verify CONTRACT_ADDR --network polygon
+```

hardhat.config.ts

@@ -9,6 +9,7 @@ const INFURA_API_KEY = process.env.INFURA_API_KEY || 'INFURA_API_KEY'
 const ALCHEMY_API_KEY = process.env.ALCHEMY_API_KEY || 'ALCHEMY_API_KEY'
 const PRIVATE_KEY = process.env.PRIVATE_KEY
 const MNEMONIC = process.env.MNEMONIC
+const POLYGONSCAN_KEY = process.env.POLYGONSCAN_API_KEY || ''
 const solidityVersions = ["0.6.0", "0.6.2", "0.6.6", "0.8.18", "0.8.20"]
 const compilers = solidityVersions.map((version) => ({
   version,
@@ -72,6 +73,13 @@ const config: HardhatUserConfig = {
     tests: './test',
     cache: './cache',
     artifacts: './artifacts'
+  },
+  etherscan: {
+    // your API Key from PolygonScan
+    // Obtain one at https://polygonscan.com/
+    apiKey: {
+      polygon: POLYGONSCAN_KEY
+    }
   }
 }