upgraded to react router v4

frontend/components/DropdownMenu/DropdownMenu.js

@@ -1,31 +1,20 @@
 // @flow
 import React from 'react';
-import { browserHistory } from 'react-router';
 
 import styles from './DropdownMenu.scss';
 
-class MenuItem extends React.Component {
-  onClick = () => {
-    if (this.props.to) {
-      browserHistory.push(this.props.to);
-    } else {
-      this.props.onClick();
-    }
-  };
-
-  render() {
-    return (
-      <div className={styles.menuItem} onClick={this.onClick}>
-        {this.props.children}
-      </div>
-    );
-  }
-}
-
-MenuItem.propTypes = {
-  onClick: React.PropTypes.func,
-  to: React.PropTypes.string,
-  children: React.PropTypes.node.isRequired,
+const MenuItem = ({
+  onClick,
+  children,
+}: {
+  onClick?: Function,
+  children?: React.Element<any>,
+}) => {
+  return (
+    <div className={styles.menuItem} onClick={onClick}>
+      {children}
+    </div>
+  );
 };
 
 //