Misc fixes (#713)

* Upgrade demo app to 7.1

* Test pass except for demo

* RuboCop fixes

* Schema without version for older Rails

* Remove unneeded migrations.

* WIP

* Remove package-lock.json

* Remove unnecessary require of bootstrap_form

* belongs_to defaults to required

* Update bundler version and cleanup

Author: lcreid

README.md

@@ -1064,7 +1064,7 @@ will be rendered as:
       </div>
     </div>
   </trix-toolbar>
-  <trix-editor aria-label="Life story" class="trix-content form-control" contenteditable="" data-blob-url-template="http://test.host/rails/active_storage/blobs/redirect/:signed_id/:filename" data-direct-upload-url="http://test.host/rails/active_storage/direct_uploads" id="user_life_story" input="user_life_story_trix_input_user" role="textbox" toolbar="trix-toolbar-1" trix-id="1">
+  <trix-editor aria-label="Life story" class="trix-content form-control" contenteditable="" data-blob-url-template="http://shell:3001/rails/active_storage/blobs/redirect/:signed_id/:filename" data-direct-upload-url="http://shell:3001/rails/active_storage/direct_uploads" id="user_life_story" input="user_life_story_trix_input_user" role="textbox" toolbar="trix-toolbar-1" trix-id="1">
   </trix-editor>
 </div>
 ```

demo/config/application.rb

@@ -5,7 +5,6 @@
 # Require the gems listed in Gemfile, including any gems
 # you've limited to :test, :development, or :production.
 Bundler.require(*Rails.groups)
-require "bootstrap_form"
 
 module Dummy
   class Application < Rails::Application