Add pdf.js reader

README.md

@@ -34,3 +34,9 @@ python3 manage.py migrate
 # Run development server
 python3 manage.py runserver
 ```
+
+## Credits
+- KoReader: https://github.com/koreader/koreader/ (AGPL 3.0)
+- KoReader Sync Server: https://github.com/koreader/koreader-sync-server/ (AGPL 3.0)
+- PDF.js: https://mozilla.github.io/pdf.js/ (Apache 2.0)
+- EPUB.js: https://github.com/futurepress/epub.js (Copyright)