Update webpack config

- write bundle to `/build`
- add support for SASS
- improve options view as a proof o concept for styling

src/js/components/Bubble.js

@@ -1,43 +1,44 @@
-import React, { Component, Fragment } from 'react'
-import Modal, { Content } from 'components/Modal'
-import Form from 'components/Form'
-import { observable } from 'mobx'
-import { observer } from 'mobx-react'
+import React, { Component } from "react";
+import Modal, { Content } from "components/Modal";
+import Form from "components/Form";
+import { observable } from "mobx";
+import { observer } from "mobx-react";
+import logoUrl from "../../images/logo.png";
 
 @observer
 class Bubble extends Component {
-  @observable open = false
+  @observable open = false;
 
-  onOpen = (_e) => {
-    this.open = true
-  }
+  onOpen = _e => {
+    this.open = true;
+  };
 
-  onClose = (_e) => {
-    this.open = false
-  }
+  onClose = _e => {
+    this.open = false;
+  };
 
   // RENDER -------------------------------------------------------------------
 
   render() {
     return (
-      <Fragment>
+      <>
         <img
           onClick={this.onOpen}
-          src={chrome.extension.getURL('src/images/logo.png')}
+          src={chrome.extension.getURL(logoUrl)}
           width="50%"
         />
 
-        {this.open &&
+        {this.open && (
           <Modal>
             <Content>
               <Form />
               <button onClick={this.onClose}>Close</button>
             </Content>
           </Modal>
-        }
-      </Fragment>
-    )
+        )}
+      </>
+    );
   }
 }
 
-export default Bubble
+export default Bubble;