Added "The Little Book of Rust Macros"

README.md

@@ -191,6 +191,11 @@ This book describes web development using the Rust programming language and will
 
 Finally, you will be taken through examples of how to test and debug microservices and pack them to a tiny monolithic binary or put it into a container and deploy it to modern cloud platforms such as AWS.
 
+### [The Little Book of Rust Macros](https://danielkeep.github.io/tlborm/book/index.html) *Free* (this is a work in progress)
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+This book is an attempt to distil the Rust community's collective knowledge of Rust macros. The book will introduce Rust's Macro-By-Example system: *macro_rules!*. Rather than trying to cover it based on practical examples, it will instead attempt to give you a complete and thorough explanation of how the system works. As such, this is intended for people who just want the system as a whole explained, rather than be guided through it.
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 **Resources**
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