Webpack Upgrade

[btyy77c]

Context

• Fixes #604
• Upgrade Webpack from 3.x to 4.x

Summary of Changes

• Upgrade webpacker gem to version 4
• Added/Upgraded @rails/ujs, @rails/webpacker, rails-erb-loader, and webpack-dev-server packages
• Changed webpack configuration files to work with webpack 4
• Changed "include PgSearch" to "include PgSearch::Model" due to warnings in tests
• Added .dockerignore file. Sometimes your outdated node_modules from your local computer can be pulled into your docker environment. It can cause problems when trying to compile your assets inside docker. Also, things like the .git folder will make your docker image larger without adding any value. Adding a .dockerignore file will help keep these files out of your docker image.

Checklist

• [ ] Tested Mobile Responsiveness
• [ ] Added Unit Tests
• [ ] CI Passes
• [ ] Deploys to Heroku on test Correctly (Maintainers will handle)
• [ ] Added Documentation (Service and Code when required)

Screenshots

Before

After

[DeeDeeG]

Travis CI error is unrelated to these changes. Thank you! Overall this looks good!

In my practical testing, all of the site's functionality that I can test in Docker was working.

Key things that were checked:

• Submitting new restrooms works
  • Submitted a dummy restroom entry
  • Geocoding is expected to fail, without providing a valid Google Geocoding API key, not related to these changes.
• Searching for existing restrooms works
  • Search "San Francisco" to get the entries that are pre-seeded in the testing environment
• Splash page works
  • Search box, search by text, search by location all appear to work as intended.
• Static pages (about, business info, restroom PDF signs) appear as normal
• Contact form works as intended
• Pages for individual restrooms appear to work
  • "Propose an edit" functionality appears to work
  • Thumbs up / Thumbs down buttons work, ratings are updated, stored and displayed.
• API demo page appears to work correctly
  • Dummy restroom I added during testing shows up as the most-recent entry in the database

Not checked (I don't know how to check these at this time):

• Admin account login process
• Confirming a proposed restroom edit as an admin

[DeeDeeG]

I'm going to merge this, despite the failing tests, because (as you have pointed out, and I have confirmed) these same tests pass on the develop branch, on commits that previously passed. As such, these changes did not cause the tests to fail.

I will make some tweaks to follow up on this PR, as mentioned in my review comments.

(Please note that we have recently changed the merge policy to use only "squash" merges. So, for the time being, this and all future Pull Requests will be squashed into a single commit when merged.)

Thank you for doing this upgrade!