Add (vague) instructions to adding a new network to the dropdown.

README.md

@@ -168,3 +168,28 @@ To delete a notice:
 npm run deleteNotice
 ```
 A list of active notices will pop up. Enter the corresponding id in the command line prompt and add and commit the new changes afterwards.
+
+## Adding Custom Networks
+
+To add another network to our dropdown menu, make sure the following files are adjusted properly:
+
+```
+app/scripts/config.js
+app/scripts/lib/buy-eth-url.js
+app/scripts/lib/config-manager.js
+ui/app/app.js
+ui/app/components/buy-button-subview.js
+ui/app/components/drop-menu-item.js
+ui/app/components/network.js
+ui/app/components/transaction-list-item.js
+ui/app/config.js
+ui/app/css/lib.css
+ui/lib/account-link.js
+ui/lib/explorer-link.js
+```
+
+You will need:
++ The network ID
++ An RPC Endpoint url
++ An explorer link
++ CSS for the display icon