<issue_start><issue_comment>Title: [Question] How can I save image using path?
username_0: Hello guys.

I used paperclip (without mongoid) in another project and I could make this.
I have this model:

```ruby
class Picture
  include Mongoid::Document
  include Mongoid::Paperclip

  has_mongoid_attached_file :avatar
end
```

I tried make this:
```ruby
picture = Picture.new
picture.avatar = File.open ('/path/to/my/image.jpg') # ERROR!
```

`Paperclip::Errors::MissingRequiredValidatorError: Paperclip::Errors::MissingRequiredValidatorError`

In paperclip this works. How can I add an image by path in my model?

Thanks for this.
<issue_comment>username_0: validates_attachment_content_type :avatar, :content_type => ["image/jpg", "image/jpeg", "image/png", "image/gif"]

Sorry for this issue!<issue_closed>