add library functionality to app

Author: unknown

Procfile

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+web: npm run start

README.md

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 # booklibrary
-an express js app the manages books in a library 
+An express js app the manages books in a library 
+
+## **API endpoints**
+`- GET /api/ilbrary - Get all books available` 
+`- GET /api/ilbrary/<book_id> - Get book by Id` 
+`- POST /api/ilbrary - Add new book to the library` 
+`- DELETE /api/ilbrary - Remove a book from the library`