Update README.md

README.md

@@ -1,5 +1,6 @@
 # Table of Contents
 
+* [Implementing Hashable in Dart](https://github.com/vandadnp/flutter-tips-and-tricks/blob/main/README.md#implementing-hashable-in-dart)
 * [Random Name Generator in Dart](https://github.com/vandadnp/flutter-tips-and-tricks/blob/main/README.md#random-name-generator-in-dart)
 * [Capturing Stack Traces in Dart Exceptions](https://github.com/vandadnp/flutter-tips-and-tricks/blob/main/README.md#capturing-stack-traces-in-dart-exceptions)
 * [Removing Duplicates from Lists in Dart](https://github.com/vandadnp/flutter-tips-and-tricks/blob/main/README.md#removing-duplicates-from-lists-in-dart)
@@ -42,6 +43,10 @@
 * [Extract Minimum and Maximum Values in `List<num>` in Dart](https://github.com/vandadnp/flutter-tips-and-tricks/blob/main/README.md#4-lines-of-dart-code-that-include-the-spread-operator-cascade-operator-generics-extensions-private-prefix-and-getters)
 * [Functions as First Class Citizens in Dart](https://github.com/vandadnp/flutter-tips-and-tricks/blob/main/README.md#functions-as-first-class-citizens-in-dart)
 
+# Implementing Hashable in Dart
+
+![](images/implementing-hashable-in-dart.jpg)
+
 # Random Name Generator in Dart
 
 ![](images/random-name-generator-in-dart.jpg)