Many bug fixes and improvements (#1270)

* Add Ruby and Kotlin icons
Add the avatar of @curtishd

* Update README

* Synchronize zh-hant and zh versions.

* Translate the pythontutor blocks to traditional Chinese

* Fix en/mkdocs.yml

* Update the landing page of the en version.

* Fix the Dockerfile

* Refine the en landingpage

* Fix en landing page

* Reset the README.md

zh-hant/codes/kotlin/chapter_dynamic_programming/climbing_stairs_dp.kt

@@ -27,9 +27,7 @@ fun climbingStairsDPComp(n: Int): Int {
     var a = 1
     var b = 2
     for (i in 3..n) {
-        val tmp = b
-        b += a
-        a = tmp
+        b += a.also { a = b }
     }
     return b
 }