```ruby
class String
  def truncate(position, omission = '…')
    if self.length > position
      self.slice(0, position).concat(omission)
    else
      self
    end
  end
end
```

Set ellipsis as the only truncation character
user
```ruby
class String
  def truncate(position)
    if self.length > position
      self.slice(0, position).concat('…')
    else
      self
    end
  end
end
```
assistant