Due to https://github.com/docker/docker/issues/9298 it is a huge pain
to remove ENV vars when composing images, allow us to simply treat "blank"
as a ENV var that is not being shadowed. In general we always supply a
value to ENV vars we are shadowing.
Since rspec-rails 3, the default installation creates two helper files:
* `spec_helper.rb`
* `rails_helper.rb`
`spec_helper.rb` is intended as a way of running specs that do not
require Rails, whereas `rails_helper.rb` loads Rails (as Discourse's
current `spec_helper.rb` does).
For more information:
https://www.relishapp.com/rspec/rspec-rails/docs/upgrade#default-helper-files
In this commit, I've simply replaced all instances of `spec_helper` with
`rails_helper`, and renamed the original `spec_helper.rb`.
This brings the Discourse project closer to the standard usage of RSpec
in a Rails app.
At present, every spec relies on loading Rails, but there are likely
many that don't need to. In a future pull request, I hope to introduce a
separate, minimal `spec_helper.rb` which can be used in tests which
don't rely on Rails.
If a site setting has `shadowed_by_global: true` then, if
a `GlobalSetting` exists with the same name then that value
will be used instead. Additionally, the setting will be hidden.
This is useful in a multisite environment for private settings
such as API keys. You want to set it globally, yet not display
the key to customers.
