Add rake task `rubocop:todo:generate`

This is a wrapper around

    bundle exec rubocop --auto-gen-config --auto-gen-only-exclude \
    --exclude-limit=100000

doc/development/contributing/style_guides.md

@@ -177,11 +177,10 @@ This ensures that our list isn't mistakenly removed by another auto generation o
 the `.rubocop_todo.yml`. This also allows us greater visibility into the exceptions
 which are currently being resolved.
 
-One way to generate the initial list is to run the `todo` auto generation,
-with `exclude limit` set to a high number.
+One way to generate the initial list is to run the Rake task `rubocop:todo:generate`:
 
 ```shell
-bundle exec rubocop --auto-gen-config --auto-gen-only-exclude --exclude-limit=100000
+bundle exec rake rubocop:todo:generate
 ```
 
 You can then move the list from the freshly generated `.rubocop_todo.yml` for the Cop being actively

doc/development/rake_tasks.md

@@ -188,6 +188,17 @@ Alternatively you can use the following on each spec run,
 bundle exec spring rspec some_spec.rb
 ```
 
+## Generate initial RuboCop TODO list
+
+One way to generate the initial list is to run the Rake task `rubocop:todo:generate`:
+
+```shell
+bundle exec rake rubocop:todo:generate
+```
+
+See [Resolving RuboCop exceptions](contributing/style_guides.md#resolving-rubocop-exceptions)
+on how to proceed from here.
+
 ## Compile Frontend Assets
 
 You shouldn't ever need to compile frontend assets manually in development, but

lib/tasks/rubocop.rake

@@ -4,4 +4,21 @@ unless Rails.env.production?
   require 'rubocop/rake_task'
 
   RuboCop::RakeTask.new
+
+  namespace :rubocop do
+    namespace :todo do
+      desc 'Generate RuboCop todos'
+      task :generate do
+        require 'rubocop'
+
+        options = %w[
+          --auto-gen-config
+          --auto-gen-only-exclude
+          --exclude-limit=100000
+        ]
+
+        RuboCop::CLI.new.run(options)
+      end
+    end
+  end
 end