added maps to listings and corrected minor typo (cc @hackeryarn)

README.md

@@ -28,11 +28,12 @@ If there's no link, it's not done yet! [why not contribute?](contributing.md)
 5. [Arrays and slices](arrays-and-slices.md) - Learn about arrays, slices, `len`, varargs, `range` and test coverage.
 6. [Structs, methods & interfaces](structs-methods-and-interfaces.md) - Learn about `struct`, methods, `interface` and table driven tests.
 7. [Pointers & errors](pointers-and-errors.md) - Learn about pointers and errors.
-8. [Dependency Injection](dependency-injection.md) - Learn about dependency injection, how it relates to using interfaces and a primer on io.
-9. [Mocking](mocking.md) - Take some existing untested code and use DI with mocking to test it.
-10. [Concurrency](concurrency.md) - Learn how to write concurrent code to make your software faster.
-11. [Select](select.md) - Learn how to synchronise asynchronous processes elegantly.
-11. [Reflection (WIP)](reflection.md) - Learn about reflection
+8. [Maps](maps.md) Learn about storing values in the map data structure.
+9. [Dependency Injection](dependency-injection.md) - Learn about dependency injection, how it relates to using interfaces and a primer on io.
+10. [Mocking](mocking.md) - Take some existing untested code and use DI with mocking to test it.
+11. [Concurrency](concurrency.md) - Learn how to write concurrent code to make your software faster.
+12. [Select](select.md) - Learn how to synchronise asynchronous processes elegantly.
+13. [Reflection (WIP)](reflection.md) - Learn about reflection
 
 Property-based tests \(todo\)
 

SUMMARY.md

@@ -11,6 +11,7 @@
 * [Arrays and slices](arrays-and-slices.md)
 * [Structs, methods & interfaces](structs-methods-and-interfaces.md)
 * [Pointers & errors](pointers-and-errors.md)
+* [Maps](maps.md)
 * [Dependency Injection](dependency-injection.md)
 * [Mocking](mocking.md)
 * [Concurrency](concurrency.md)

maps.md

@@ -3,7 +3,7 @@
 **[You can find all the code for this chapter
 here](https://github.com/quii/learn-go-with-tests/tree/master/maps)**
 
-In the previous chapter, you saw how to store values in order. Now, we will
+In [arrays & slices](arrays-and-slices.md), you saw how to store values in order. Now, we will
 look at a way to store items by a `key` and look them up quickly.
 
 Maps allow you to store items in a manner similar to a dictionary. You can
@@ -73,7 +73,7 @@ func Search(dictionary map[string]string, word string) string {
 }
 ```
 
-Getting a value our of a Map is the same as getting a value out of Array
+Getting a value out of a Map is the same as getting a value out of Array
 `map[key]`.
 
 ## Refactor