* Rendered a static reading list button to each bookcard component
* Attached click listener to bookmark button to log book data
* Clicking bookmark button saves book information to a localStorage array
* Updated card height to account for button
* Updated saveBookToLocalStorage function to use objects instead of arrays
* Can now toggle books in and out of localStorage
* Reverted previous 4 commits so that data isn't directly written to localStorage
* Created a sidebar link to reading list
* Added placeholder bookmarks page
* Bookmark button now updates state in index.js
* Initialized context API
* Wrote a reducer function to handle bookmark state changes
* Configured reducer to add books in and out of state
* Reading list is now preserved between state AND localStorage when changing categories
* Fixed some code format issues
* Rendered saved books in reading list component
* Toggle apperance of bookmark button
* Hacky fix for positioning of reading list sidebar link
* Adjusted style and alignment of bookmark button
* Added check to determine if window is defined in useEffect
* Exported the gatsby-ssr API
