Remove FACTER_govuk_platform

[samjsharpe]

This environment variable is set by puppet. It should not be used by applications and it is being removed from our environment.

I have:

• replaced ENV['FACTER_govuk_platform'] in the code
• removed a test for it
• removed the legacy router.rake task completely (it's not used)

This fixes #179

[matthewford]

@samjsharpe If this is going - I am happy to merge this just sad :panda_face: as then we will not be able to distinguish sync error email by platform.

[samjsharpe]

You can't do that anyway... In all our environments except development and ci, govuk_platform is already set to 'production' so from the application perspective .platform is almost always production.

[samjsharpe]

I audited the current value of FACTER_govuk_platform in all our environments: https://github.com/alphagov/whitehall/commit/08c124743701b0019d0fce88e245c1c2e523351c

There are ways to distinguish environments, as the ORGANISATION env var is available on the deploy jenkins machines as that's how we can specify different initializers per organisation.

I think that's actually how you are currently distinguishing between emails:

[alphagov-deployment/trade-tariff-backend:master●]$ grep MAILER_ENV initializers_by_organisation/*/mailer_env.rb
initializers_by_organisation/preview/mailer_env.rb:MAILER_ENV="preview"
initializers_by_organisation/production/mailer_env.rb:MAILER_ENV="production"
initializers_by_organisation/staging/mailer_env.rb:MAILER_ENV="staging"

[matthewford]

@samjsharpe I've rebased your branch - we can merge this in as we now store the sync errors in the db to be viewed in the admin interface, so the platform is less of an issue. Typically if there is a problem it is happening on all envs anyway.

Ideally we replace this with a constant that is set on alphagov-deployment for clarity.

[matthewford]

Just reread the comment about MAILER_ENV so ignore that last part of my previous comment