Improve TOC

Author: madeindjs

rails6/en/chapter01-introduction.adoc

@@ -11,6 +11,7 @@ The purpose of this book is not only to teach you how to build an API with Rails
 - Building JSON responses
 - Test your end-points with unit and functional tests
 - Set up authentication with JSON Web Tokens (JWT)
+- Use JSON:API specification
 - Optimize and cache the API
 
 I strongly recommend you follow all the steps in this book. Try not to skip chapters because I will give you some tips and tricks to improve your skills throughout the book. You can consider yourself the main character of a video game who gain a level in each chapter.

rails6/en/chapter03-presenting-users.adoc

@@ -1,5 +1,5 @@
 [#chapter03-presenting-users]
-= Presenting the users
+= Presenting users
 
 In the last chapter we manage to set up the bare bones for our application endpoints configuration.
 

rails6/en/chapter04-athentification.adoc

@@ -1,5 +1,5 @@
 [#chapter05-athentification]
-= Authenticating users
+= Authenticating user
 
 It's been a long time since you started. I hope you enjoy this trip as much as I do.
 

rails6/en/chapter05-user-products.adoc

@@ -1,5 +1,5 @@
 [#chapter05-user-products]
-= User products
+= User's products
 
 In the previous chapter, we implemented the authentication mechanism we will use throughout the application.
 

rails6/en/chapter06-improve-json.adoc

@@ -1,5 +1,5 @@
 [#chapter06-improve-json]
-= JSON with Active Model Serializers
+= JSON with JSON:API
 
 In the previous chapter we added products to the application and built all the necessary roads. We have also associated a product with an user and restricted some of the actions of `products_controller`.