Add npm start to start development node

It also creates a JSON file with addresses
of the deployed contracts.

.gitignore

@@ -1,9 +1,4 @@
 node_modules
-.env
-coverage
-coverage.json
-typechain
-
-#Hardhat files
 cache
 artifacts
+deployment-localhost.json

Readme.md

@@ -14,6 +14,13 @@ To run the tests, execute the following commands:
     npm install
     npm test
 
+To start a local Ethereum node with the contracts deployed, execute:
+
+    npm start
+
+This will create a `deployment-localhost.json` file containing the addresses of
+the deployed contracts.
+
 Overview
 --------
 

package.json

@@ -2,7 +2,8 @@
   "name": "dagger-contracts",
   "license": "MIT",
   "scripts": {
-    "test": "hardhat test"
+    "test": "hardhat test",
+    "start": "hardhat node --export 'deployment-localhost.json'"
   },
   "devDependencies": {
     "@nomiclabs/hardhat-ethers": "^2.0.2",