Add links to some interesting resources

How to Avoid Fighting Rust Borrow Checker is a very good and detailed guide to borrow checker. I imagine it will be of great interest to Rust newbies who are still getting used to the language, since the borrow checker is the greatest cause of complaints and confusion for Rust newbies.
I haven't read the book Introduction to Programming Using Entity-Component-Systems And Existence-Based Processing yet, but it is of interest to me, since I am interested in learning how an entity-component-system program works.