Ruby 2.2.2 and up support only.
No more rake commands! Everything is available through the rails command, migrations, everything. Happy days.
Snappier dev mode: Evented file system! Basically that means it just checks for files that have changed and reloads those, it does not have to traverse all files on each request. Huge speed boost from that.
Rails API is being merged into Rails.
ActionCable (https://www.youtube.com/watch?v=n0WUjGkDFS0 by David Heinemeier Hansson)
ApplicationController.render - Basically made to work with ActionCable, it allows ActionController::Renderer to render partials as strings.
where.or: Finally, with ActiveRecord we can now do Object.where(‘something = something’).or(Object.where(‘something = something else’))
Couple other things...
belongs_to has a sane required by default option, yup, its pretty rare that you want an optional belongs_to relationship. if you don’t want this behaviour a simple optional: true will fix that
turbolinks 3, respects redirects and replaces on redirect, transfer elements from page to page along with their state using "data-turbolinks-permanent", which is good for things like navigation.
has_secure_token: easy random tokens, this will save you having to have your own methods to generate if you just want something simple such as an invite token or confirmation token. Includes the ability to regenerate the token as well. Rad.
Attributes API: you can define custom attributes for your models or override existing attributes. Basically allows you to define things like defaulting money values to a particular format.
http://nithinbekal.com/posts/rails-5-features/ https://intercityup.com/blog/upcoming-changes-in-rails-5-0.html http://www.sitepoint.com/whats-new-rails-5/ http://blog.michelada.io/whats-new-in-rails-5 http://kryptonlabs.com/blog/2015/10/25/whats-new-in-rails-5/