Bump rails to 7 and get tests passing. Also modified rakefile so rake

command would continue to run rspec as the default command.  Added
stylesheets to assets.rb so they'll be included when precompiling
assets in production.

Gemfile

@@ -7,13 +7,15 @@ git_source(:github) do |repo_name|
 end
 
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
-gem 'rails', '~> 6.1.4.4'
+gem 'rails', '~> 7.0.1'
+gem 'sprockets-rails'
+
 gem 'pg'
 
 # Use Puma as the app server
 gem 'puma', '>= 5.5.2'
 # Use SCSS for stylesheets
-gem 'sassc-rails', require: false
+# gem 'sassc-rails', require: false
 # Use Uglifier as compressor for JavaScript assets
 gem 'uglifier', '>= 1.3.0'
 # See https://github.com/rails/execjs#readme for more supported runtimes
@@ -70,7 +72,6 @@ group :development do
   gem 'rubocop', require: false
   gem 'seed_dump'
   gem 'spring'
-  gem 'spring-watcher-listen', '~> 2.0.0'
 end
 
 group 'test' do