Chris Beely wrote Web Application Development with R using Shiny, second edition, published by Packt Publishing January 2016
Shiny is based on bootstrap.
This is a good book to read even if you were not planning on using Shiny because it covers a lot about web app development.
I have found R and Shiny a useful tool for data scientists to communicate with developers. It make great mock-ups.
The code for the book is on packtpub.com