Add element id's and their documentation

src/ui/components/menu/Divider.tsx

@@ -5,8 +5,8 @@ import './Divider.css'
 export default class Divider extends React.Component {
   render() {
     return (
-      <div className="Divider">
-        <div className="DividerLine"></div>
+      <div className="Divider" id={'dividerContainer'}>
+        <div className="DividerLine" id={'dividerLine'}></div>
       </div>
     )
   }