feat(jest): move into its own file

I think this will be a breaking change, but I'm not a hundred percent sure.

I'm also not too sure how to test this

README.md

@@ -66,6 +66,33 @@ module.exports = {
 }
 ```
 
+### Jest
+
+We recommend using Jest as a test runner.
+
+**terminal**
+```sh
+yarn add eslint-plugin-jest --dev
+```
+
+**.eslintrc.js**
+```js
+module.exports = {
+  extends: 'algolia/jest'
+};
+```
+
+**package.json**
+```json
+{
+  "scripts": {
+    "test": "npm run lint",
+    "lint": "eslint .",
+    "lint:fix": "npm run lint -- --fix"
+  }
+}
+```
+
 ### React
 
 **terminal**

base.js

@@ -4,7 +4,6 @@ module.exports = {
     browser: true,
     es6: true,
     node: true,
-    jest: true,
   },
   parser: 'babel-eslint', // allows both flowtype and static class properties
   parserOptions: {
@@ -16,11 +15,10 @@ module.exports = {
       jsx: true,
     },
   },
-  plugins: ['import', 'jest', 'prettier'],
+  plugins: ['import', 'prettier'],
   extends: [
     'eslint:recommended',
     'plugin:import/errors',
-    'plugin:jest/recommended',
     './rules/base.js',
     'prettier',
   ],

jest.js

@@ -0,0 +1,8 @@
+// eslint-disable-next-line import/no-commonjs
+module.exports = {
+  env: {
+    jest: true,
+  },
+  extends: ['plugin:jest/recommended', './base.js'],
+  plugins: ['jest'],
+};