Added Dart Programming (#4479)

* Added Dart Programming

* Added dart programing language

free-courses-en.md

@@ -11,6 +11,7 @@
 * [Clojure](#clojure)
 * [Compilers](#compilers)
 * [CUDA](#cuda)
+* [Dart](#dart)
 * [Data Science](#data-science)
 * [Databases](#databases)
 * [Deep Learning](#deep-learning)
@@ -155,6 +156,13 @@
 * [Intro to Parallel Programming Using CUDA to Harness the Power of GPUs](https://www.udacity.com/course/intro-to-parallel-programming--cs344) (Udacity)
 
 
+### Dart
+
+* [Dart Course for Beginners](https://www.udemy.com/course/dartlang) (Udemy)
+* [Dart Programming Tutorial - Full Course](https://www.youtube.com/watch?v=Ej_Pcr4uC2Q) - FreeCodeCamp
+* [Dart Programming Tutorial | Learn the Dart for Flutter](https://www.udemy.com/course/dart-programming-tutorial-learn-the-dart-for-flutter) (Udemy)
+
+
 ### Data Science
 
 * [Advanced Data Mining with Weka MOOC](https://www.cs.waikato.ac.nz/ml/weka/mooc/advanceddataminingwithweka/)