[don't merge] Refactor CSS assets to use Sprockets instead of Webpack

[Bodacious]

Fixes #1862, #1762

Changes proposed in this PR:

• Move CSS files into app/assets
• Use Sprockets for SCSS compilation
• Update rake assets:precompile to support JS and CSS

[briri]

Changes look ok. Its really hard to tell though if there are any visual issues with the CSS reorg without running and visually inspecting the site.

Why move back over to Sprockets (aside from being more Rails-ish)? What advantage are we gaining? We would still need to support Webpack to handle our ES6 JS.

[jollopre]

If I remember well, we decided to move towards npm to handle front-end related issues since they are more actively maintained than front-end assets handled through ruby gems.

Although these changes certainly keep the codebase more Rails focused, I got my doubts whether or not it is an appropriate move knowing that Rails 5 introduced Webpack on their assets pipeline...

[xsrust]

Really like the refactoring out of variables and hierarchical layout.

I'll need to have a look through all the customization we're using and make sure everything we're changing is captured in the variables.

[Bodacious]

Readme should be updated to include:

Assets Management

Javascripts

Javascript are written using ES6 and can be found in app/assets/javascripts. The application uses the recommended configuration for using Webpack in Rails 5: the webpacker gem.

You don't have to run a separate process for Webpack for JS to be compiled. This is compiled automatically on each request (in development).

Be sure to check the Rails log if you are seeing unexpected Javascript behaviour. There's an ESLint check run each time the assets are compiled, and errors are reported in the Rails log.

Stylesheets, images and other assets

Stylesheets are written using Sassy CSS (via lib-c SASS)

Stylesheets use Rails' asset pipeline for compilation. For more information on how that is configured, please read this guide: https://guides.rubyonrails.org/asset_pipeline.html

Compiling

To compile assets for development, please use the rake task rake assets:precompile

[briri]

👍 The changes look fine to me. I will need to do some updating of the customized CSS for the DMPTool once this is in place.

It would be good to write up some recommendations/suggestions for how to go about customizing the CSS for local installations.

Feel free to merge into dev while I'm away

[xsrust]

@Bodacious as this is pointed at the next-sprint branch, is there still reason not to merge it into that branch?

[Bodacious]

@xsrust Let me have another look at it and make sure it's ready.

[Bodacious]

Please ignore this. Prefer #1962

[briri]

would suggest just closing this PR in favor of #1962