Update README.md

tkgauri · web-flow · commit 86fbe214061e · 2019-05-20T14:09:17.000+09:00
Change md syntax highlighting for installation command, from ruby to sh
diff --git a/README.md b/README.md
@@ -29,8 +29,8 @@ bundle
 
 Or install it yourself as:
 
-```ruby
-gem install 'line-bot-api'
+```sh
+gem install line-bot-api
 ```
 
 ## Synopsis
