Support Rails 5

[cbeer]

Tracking upstream issues:

• Support turbolinks 5.x events, while maintaining backwards compatibility blacklight#1425
• Rails 5 issue: acts-as-taggable-on 3.5.0 has a dependency on activerecord < 5 mbleigh/acts-as-taggable-on#762
• Add Rails 5 support heartcombo/mail_form#46 (removed dependency)
• Relax rails dependency to support Rails 5 madebymany/sir-trevor-rails#52
• breadcrumbs_on_rails (rails 5 ActionController:API weppos/breadcrumbs_on_rails#82)

[jcoyne]

It looks like a fix for the second bullet has been merged into master. So we just await a new release (3.6.0 perhaps?) of acts-as-taggable-on

[jcoyne]

@cbeer how do you feel about pointing at the master branch of AATO?

[cbeer]

🤷 .. I'm hoping they'll get a release out soon enough.

[cbeer]

We're also waiting for mail_form, apparently, used only by ContactForm. Maybe we can just sever that dependency and just use actionmailer (since it seems to be pretty lightly maintained..)?

[cbeer]

and breadcrumbs_on_rails; maybe replace it with https://github.com/lassebunk/gretel?

[jcoyne]

There is a 4.0.0.pre release version of AATO