Add Graphql course (#8739)

more/free-programming-interactive-tutorials-en.md

@@ -15,6 +15,7 @@
 * [Git](#git)
 * [GLSL](#glsl)
 * [Go](#go)
+* [GraphQL](#graphql)
 * [Haskell](#haskell)
 * [HTML and CSS](#html-and-css)
     * [Bootstrap](#bootstrap)
@@ -158,6 +159,11 @@
 * [The Go Tutorial](http://tour.golang.org)
 
 
+### GraphQL
+
+* [Apollo Odyssey](https://www.apollographql.com/tutorials/)
+
+
 ### Haskell
 
 * [Try Haskell!](http://tryhaskell.org)