rails 4.1 supprt

I fix gem to execute on rails 4.1.
Rails 4.1 changed finicky about assets files, so it raised error message to "couldn't find file 'fancybox_nav_left.png'".
I change 'css.erb' to 'scss' and image loading method.

But it support rails 4.1 yet.

For example below code is include error.

```ruby
class Payment < ActiveRecord::Base
  enum status: %i[reserve ok cancel suspend]
end
```

ActiveRecord#enum generate Payment.statuses method and confilict typus's selector function.
http://docs.typuscmf.com/configuration/resources.html#selectors

I thinked and decided this problem separate into above prolem.