add bootstrap to gatsby

JavaScript
import React from 'react';
import '../path_to/bootstrap.min.css';

const MyComponent = () => (
    <div>
        <p>This contains a button which uses the bootstrap.css</p>
        <button class="btn btn-primary">Click me</button>
    </div>
);import React from 'react';
import { Button } from 'react-bootstrap';

const MyComponent = () => (
      <div>
        <p>This contains a button which is exported by react-bootstrap</p>
        <Button variant="primary">Primary</Button>
    </div>
);npm install --save react-bootstrap
npm install --save bootstrap
Source

Also in JavaScript: