react tutorial: add deploy steps

package.json

@@ -3,6 +3,7 @@
   "author": "caleb pollman",
   "version": "0.1.0",
   "private": true,
+  "homepage": "https://egraumann.github.io/react-calculator/",
   "engines": {
     "node": "12.13.1",
     "npm": "6.12.1"
@@ -12,28 +13,34 @@
     "react-dom": "^16.12.0"
   },
   "devDependencies": {
-    "enzyme": "^3.10.0",
-    "enzyme-adapter-react-16": "^1.15.1",
+    "enzyme": "^3.11.0",
+    "enzyme-adapter-react-16": "^1.15.2",
     "enzyme-to-json": "^3.4.3",
     "prettier": "^1.19.1",
-    "react-scripts": "3.2.0",
+    "react-scripts": "^3.3.0",
     "react-test-renderer": "^16.12.0"
   },
   "scripts": {
     "start": "react-scripts start",
     "build": "react-scripts build",
-    "test": "react-scripts test --env=jsdom",
-    "eject": "react-scripts eject"
+    "test": "react-scripts test",
+    "eject": "react-scripts eject",
+    "predeploy": "npm run build",
+    "deploy": "gh-pages -d build"
   },
-  "browserslist": [
-    ">0.2%",
-    "not dead",
-    "not ie <= 11",
-    "not op_mini all"
-  ],
-  "jest": {
-    "snapshotSerializers": [
-      "enzyme-to-json/serializer"
+  "eslintConfig": {
+    "extends": "react-app"
+  },
+  "browserslist": {
+    "production": [
+      ">0.2%",
+      "not dead",
+      "not op_mini all"
+    ],
+    "development": [
+      "last 1 chrome version",
+      "last 1 firefox version",
+      "last 1 safari version"
     ]
   }
 }