```ruby
class TipMailer < ActionMailer::Base

  layout 'email'

  def tipped(tip_id)
    @tip = Tip.find(tip_id)
    @user = @tip.to
    mail to: @user.email_address,
         subject: "#{@tip.from.username} tipped you #{@tip.cents} coins"
  end

end
```

Fix subject lines on Tip Emails.
user
```ruby
class TipMailer < ActionMailer::Base

  layout 'email'

  def tipped(tip_id)
    @tip = Tip.find(tip_id)
    @user = @tip.to
    mail to: @user.email_address,
         subject: "#{@tip.from.username} tipped you #{pluralize(@tip.cents / 100, 'coins')}"
  end

end
```
assistant