fix jquery-ui assets, for compatibility with jquery-ui-rails version 5.0.0 and below

[HusseinMorsy]

see discussion #3248

[dmitry]

That's why I don't like when any assets are in the Gemfile (and bundled with the ruby code). In my opinion javascripts, stylesheets, fonts and images should attached to the rails engine as the vendor files.

[robertomiranda]

👍

[orendon]

👍

This patch should prevail over #3258 #3254 #3251 and #3248 imho

[robertomiranda]

@orendon right, I think this the best solution at the moment

[robertomiranda]

ref #3247

[seanlinsley]

Unfortunately this doesn't actually work; ref sstephenson/sprockets#90

[robertomiranda]

seems that the solution is use require_asset instead of require ref https://github.com/sstephenson/sprockets/blob/master/lib/sprockets/context.rb#L121-L135

[seanlinsley]

Right, except the order isn't preserved: sstephenson/sprockets#90 (comment)

[HusseinMorsy]

@seanlinsley yes you are right. the solution doesn't work, because

1. the directive preprocessor always runs before the erb engine.
2. the require_asset ist not suitable, because require_asset is being added to the end of the list, instead of in the order of this file.