Merge pull request #294 from catatsuy/feature_add_rust_for_readme

add Rust implementation on README

Author: catatsuy

README.md

@@ -221,5 +221,6 @@ ISUCON過去問題の環境を「さくらのクラウド」で構築する | 
 
 ## 他の言語実装
 
+* Rust実装 https://github.com/Romira915/private-isu-rust
 * Python実装 https://github.com/methane/pixiv-isucon2016-python
 * Scala実装 https://github.com/catatsuy/private-isu/pull/140