How do I globally configure RSpec to keep the '--color' and '--format specdoc' options turned on

As you can see in the docs here, the intended use is creating ~/.rspec and in it putting your options, such as --color.

To quickly create an ~/.rspec file with the --color option, just run:

echo '--color' >> ~/.rspec 

One can also use a spec_helper.rb file in all projects. The file should include the following:

RSpec.configure do |config|
  # Use color in STDOUT
  config.color = true

  # Use color not only in STDOUT but also in pagers and files
  config.tty = true

  # Use the specified formatter
  config.formatter = :documentation # :progress, :html,
                                    # :json, CustomFormatterClass
end

Any example file must require the helper to be able to use that options.

In your spec_helper.rb file, include the following option:

RSpec.configure do |config|
  config.color_enabled = true
end

You then must require in each *_spec.rb file that should use that option.