Merge remote-tracking branch 'upstream/master'

Conflicts:
	free-programming-books-es.md
	free-programming-books-ru.md
	free-programming-interactive-tutorials-en.md

free-programming-books-ja.md

@@ -52,6 +52,7 @@
 * [R](#r)
 * [Ruby](#ruby)
 * [Sather](#sather)
+* [Scala](#scala)
 * [Scheme](#scheme)
 * [sed](#sed)
 * [Smalltalk](#smalltalk)
@@ -425,6 +426,10 @@
 * [Sather を試そう](http://www.shido.info/sather/index.html) - 紫藤貴文
 
 
+###Scala
+* [tetrix in Scala](http://eed3si9n.com/tetrix-in-scala-html5-book)
+
+
 ###Scheme
 * [Gauche ユーザリファレンス](http://practical-scheme.net/gauche/man/gauche-refj.html) - 川合史朗
 * [お気楽 Scheme プログラミング入門](http://www.geocities.jp/m_hiroi/func/scheme.html) - 広井誠