add browserstack to readme (#290)

Author: mdroidian

README.md

@@ -39,3 +39,5 @@ There are some important terms to know and have exact definitions on since they
 - `Page` - A Page is anything in Roam that was created with `[[brackets]]`, `#hashtag`, `#[[hashtag with brackets]]`, or `Attribute::`. Clicking on these links in your graph takes you to its designated page, each with its own unique title, and they have no parent.
 - `Block` - A bullet or line of text in Roam. While you can also go to pages that have a zoomed in block view, their content is not unique, and they always have one parent.
 - `Node` - A superset of `Block`s and `Page`s.
+
+This project is tested with BrowserStack.