3.0 : Embed Shortcode

Settings > Embeds : Manage embeds
Embed shortcode
Embed plugin for redactor
Copy application_helper.rb default file in installer task. this file will contain helpers which developer need to override as per application. For example gallery_shortcode. User may want to change class names or want to use different image config.

authorisation fixes
Collections in Asset selector was broken for multiple category filters like image,video