```ruby
# Be sure to restart your server when you modify this file.

# Add new mime types for use in respond_to blocks:
# Mime::Type.register "text/richtext", :rtf
# Mime::Type.register_alias "text/html", :iphone
Mime::Type.register "application/pdf", :pdf```

Remove useless PDF mime-type registration
user
```ruby
# Be sure to restart your server when you modify this file.

# Add new mime types for use in respond_to blocks:
# Mime::Type.register "text/richtext", :rtf
# Mime::Type.register_alias "text/html", :iphone
# Mime::Type.register "application/pdf", :pdf```
assistant