concord-consortium/rigse

# Rails 6 Upgrade Steps

## Done:

1. Created PT stories for all top level items in the Rails Upgrade Guide.
2. Upgraded rails gem to 6.0.3.7
  a. Pinned `bootsnap` gem to earlier version (1.4.4) based on note in the docs since we are using Ruby 2.5
  b. Unpinned `newrelic_npm` gem to fix startup error
  c. Disabled code in mime type initializer that had an empty string for the mime type - this causes a runtime error in Rails 6
  d. Set `config.hosts = nil` in application.rb - otherwise you have to whitelist all domains including dev at app.rigse.docker
  e. Added `/app/helpers/**/"` to autoload paths.  In `classic` mode now the autoloader only loads 1 subdirectory below app automatically
  f. Disabled `themes_on_rails` due to a startup error
3. Replace `themes_on_rails`
  a. ✔ refer to changes in these commits: 7190256 08d4f9da5a
    1. ✔ in `application controller:41` -- Disabled theme :get_theme
    2. ✔ in `application.rb:169`  -- loads learn/all.css
    3. ✔ added `app/assets/stylesheets/learn/all.scss`
  b. ✔ Use sass class scopes for managing styles, and project specific stylesheets
    1. ✔ app/assets/projects/projectname.sass
    2. ✔ define everything within a top scope `.{theme-name}-theme-styles` { }
    3. ✔ add a css class to the body tag matching `.{theme-name}-theme-styles` for the
    current theme.
  c. ✔ Replace theme based view templates
    1. ✔ add some partial view rendering tests (backport to master?)
      - ✔ spec for app/views/home/home.html.haml
    2. ✔ add/expand theme helper to dynamically render partials for the theme.
      - ✔ views/home/_project_info
      - ✔ views/home/_project_summary
      - ✔ views/shared/_footer
      - ✔ views/shared/_logo
    3. ✔ verify view partials rendering for mailers are needed and still work:
      - ✔ views/shared/_email_banner
      - ✔ rails/app/views/password_mailer/forgot_password.html.erb:
      - ✔ rails/app/views/portal/clazz_mailer/clazz_assignment_notification.html.erb:11
      - ✔ rails/app/views/portal/clazz_mailer/clazz_creation_notification.html.erb:11
      - ✔ rails/app/views/user_mailer/confirmation_instructions.html.erb:11
    ✔  Find all `RAILS6` comments and address them