Remove Webpacker, ActionMailer, and the like

[jelaniwoods]

Webpacker and Rails 6 has a lot of extra stuff that increases load time, that students won't need for the basic projects.

This changes in this branch:

• Adds the following flags:

  --skip-action-mailer
  --skip-javascript
  --skip-webpack-install

• Remove sass-rails, replaced with sassc-rails
• Add sprockets less than version 4
• Add gem 'execjs' and therubyracer for Gitpod
• Remove action_mailer from development.rb
• Substitute javascript_pack_tag with javascript_include_tag in application.html.erb
• Add app/assets/javascripts/application.js

Clone, checkout jw-remove-webpacker branch,

rails new no-webpack --rc=<path to fd> -m <path to template.rb> 

The new app should be able to navigate to:

• / and see "Yay, you're on Rails
• /git
• /admin and login with admin@example.com and password

Note:

There are a couple temporary changes I've made so that review is as easy as possible. In template.rb

# ENV = :prod
ENV = :dev

This change is because we're in development and the changes aren't in master yet.

In fd The removal of

--template=https://raw.githubusercontent.com/firstdraft/appdev_template/master/template.rb

For similar reasons. I will add them back after approval.

Other Note

fd is just an arbitraly named file that is used to store all the flags we run with rails new.

You can run rails to see the info:

[--rc=RC]   # Path to file containing extra configuration options for rails command

[raghubetina]

@jelaniwoods Excellent. I came to remind you not to forget to switch pack_tag for include_tag but looks like you are all over it. LGTM