title: ESLint - "Expected indentation of 0 tabs but found 4 spaces." when trying to override airbnb config
body: <p>I'm trying to set up ESLint for my project via VSCode</p>
  
  <p>I installed it and this is my <code>.eslintrc</code> file:</p>
  
  <pre><code>{
      "parser": "babel-eslint",
      "extends": "airbnb",
      "env": {
          "browser": true,
          "mocha": true,
          "node": true
      },
      "parserOptions": {
          "ecmaFeatures": {
              "experimentalObjectRestSpread": true,
              "jsx": true
          },
          "sourceType": "module"
      },
      "plugins": [
          "flowtype",
          "flowtype-errors",
          "import",
          "promise",
          "react"
      ],
      "rules": {
          "no-unused-vars": 0,
          "indent": ["error", "tab"]
      }
  }
  </code></pre>
  
  <p>But when I look at some line like this:</p>
  
  <pre><code>export function increment() {
      return {
          type: INCREMENT_COUNTER
      };
  }
  </code></pre>
  
  <p>I get these errors:</p>
  
  <pre><code>[eslint] Expected indentation of 0 tabs but found 4 spaces. (indent)
  [eslint] Expected indentation of 1 tab but found 4 spaces. (indent)
  </code></pre>
  
  <p>I think there is some conflict between the value I tried to override and between airbnb's configuration. I'm trying to set indentation to 1 tab instead of just 2 spaces</p>
  
  <p>I used this boilerplate for my project:
  <code>https://github.com/chentsulin/electron-react-boilerplate</code></p>
  
  <p>Any ideas?
  Thanks</p>