This implementation is a bit smaller and still has the following benefits:

* No need of app/javascript/packs/custom.js
For custom stylesheet, it typically has only
"require('../styles/custom.scss')" and is redundant.

* No need to extract vendor stylesheet to another asset
Extracting vendor stylesheet could be forgotten by developers who do not
use custom stylesheet.

* Fix #2922 - Load stylesheet from "custom.css" entrypoint when present

This is pretty much the same way it worked as before, albeit with
having to create app/javascript/packs/custom.js with
require('../styles/custom.scss') (or whatever you want really), which
will be a blank slate for you to import whatever you want

* Remove old assets directory

* Extract font-awesome into common.css and always load it

* Only load Intl data for current language

* Extract common chunk only from application.js and public.js

* Generate locale packs, avoid caching on window object

* Create common chunk rather than vendor chunk

vendor chunk is a set of modules provided by external vendors, but now we
can have a chunk as a set of modules shared by multiple entry points,
which could be more efficent than having vendor chunk.

* Start rails-ujs in common.js

This is used by /settings/two_factor_authentication.

* add haml_lint to Gemfile

* add .haml-lint.yml

* fix warnings of haml_lint

* Replace browserify with webpack

* Add react-intl-translations-manager

* Do not minify in development, add offline-plugin for ServiceWorker background cache updates

* Adjust tests and dependencies

* Fix production deployments

* Fix tests

* More optimizations

* Improve travis cache for npm stuff

* Re-run travis

* Add back support for custom.scss as before

* Remove offline-plugin and babili

* Fix issue with Immutable.List().unshift(...values) not working as expected

* Make travis load schema instead of running all migrations in sequence

* Fix missing React import in WarningContainer. Optimize rendering performance by using ImmutablePureComponent instead of
React.PureComponent. ImmutablePureComponent uses Immutable.is() to compare props. Replace dynamic callback bindings in
<UI />

* Add react definitions to places that use JSX

* Add Procfile.dev for running rails, webpack and streaming API at the same time

* Added different title for dev

* Changed indentation

* Set a dev specific favicon

* Consistent spacing

* Add trailing slash for consistency

* Update to remove interpolation

* Move site title helper to instance helper (name change only)

* Remove newline in <title> tag

* Add site_hostname helper method to wrap up local_domain value

* Use site_hostname helper in places that need local_domain value

* Add mask-icon (#1572)

* use updated svg logo for mask-icon

* User can create a custom.scss to customize their instance without modifying gitted files.

* Add documentation for customization.

* Forgot the helper file

* Fix Style to pass codeclimate

* Requests from maintainer.

* Add helper method to return Setting.site_title

* Use site_title helper in application layout

* Use site_title value for og:site_name

removing web app capability from non-webapp pages

See: https://dequeuniversity.com/rules/axe/2.1/html-has-lang