akiinyo/Tidy — comment on commit 52abf4d9014f8ea36be781a0324cc81e7019b8e1
File: app/models/member.rb line 9
By moro:

簡単なパターンのヒント

```ruby
[1,2,3,4,5] - [3,4] #=> [1, 2, 5]
```