title: Rails Apartment: Adding www. redirects to public tenant
body: <p>I'm having a problem with creating a multi-tenancy app with Ruby on Rails, using the apartment gem.  The problem is that whenever I add www. to the start of my web URL, it takes me back to the public tenant.  I am using Heroku and google domains to add a wildcard subdomain.   Example:  tenant1.website.com works.  www.tenant1.website.com  takes me to the public tenant. Fixes?</p>
  
  <pre><code># You can have Apartment route to the appropriate Tenant by adding some Rack middleware.
  # Apartment can support many different "Elevators" that can take care of this routing to your data.
  # Require whichever Elevator you're using below or none if you have a custom one.
  #
  # require 'apartment/elevators/generic'
  # require 'apartment/elevators/domain'
  require 'apartment/elevators/subdomain'
  # require 'apartment/elevators/first_subdomain'
  # require 'apartment/elevators/host'
  
  #
  # Apartment Configuration
  #
  Apartment.configure do |config|
  
    Apartment::Elevators::Subdomain.excluded_subdomains = ['www']
  
    # Add any models that you do not want to be multi-tenanted, but remain in the global (public) namespace.
    # A typical example would be a Customer or Tenant model that stores each Tenant's information.
    #
     config.excluded_models = %w{ User }
  
    # In order to migrate all of your Tenants you need to provide a list of Tenant names to Apartment.
    # You can make this dynamic by providing a Proc object to be called on migrations.
    # This object should yield either:
    # - an array of strings representing each Tenant name.
    # - a hash which keys are tenant names, and values custom db config (must contain all key/values required in database.yml)
    #
    # config.tenant_names = lambda{ Customer.pluck(:tenant_name) }
    # config.tenant_names = ['tenant1', 'tenant2']
    # config.tenant_names = {
    #   'tenant1' =&gt; {
    #     adapter: 'postgresql',
    #     host: 'some_server',
    #     port: 5555,
    #     database: 'postgres' # this is not the name of the tenant's db
    #                          # but the name of the database to connect to before creating the tenant's db
    #                          # mandatory in postgresql
    #   },
    #   'tenant2' =&gt; {
    #     adapter:  'postgresql',
    #     database: 'postgres' # this is not the name of the tenant's db
    #                          # but the name of the database to connect to before creating the tenant's db
    #                          # mandatory in postgresql
    #   }
    # }
    # config.tenant_names = lambda do
    #   Tenant.all.each_with_object({}) do |tenant, hash|
    #     hash[tenant.name] = tenant.db_configuration
    #   end
    # end
    #
    config.tenant_names = lambda { User.pluck :subdomain }
  
    # PostgreSQL:
    #   Specifies whether to use PostgreSQL schemas or create a new database per Tenant.
    #
    # MySQL:
    #   Specifies whether to switch databases by using `use` statement or re-establish connection.
    #
    # The default behaviour is true.
    #
    # config.use_schemas = true
  
    #
    # ==&gt; PostgreSQL only options
  
    # Apartment can be forced to use raw SQL dumps instead of schema.rb for creating new schemas.
    # Use this when you are using some extra features in PostgreSQL that can't be represented in
    # schema.rb, like materialized views etc. (only applies with use_schemas set to true).
    # (Note: this option doesn't use db/structure.sql, it creates SQL dump by executing pg_dump)
    #
    # config.use_sql = false
  
    # There are cases where you might want some schemas to always be in your search_path
    # e.g when using a PostgreSQL extension like hstore.
    # Any schemas added here will be available along with your selected Tenant.
    #
    # config.persistent_schemas = %w{ hstore }
  
    # &lt;== PostgreSQL only options
    #
  
    # By default, and only when not using PostgreSQL schemas, Apartment will prepend the environment
    # to the tenant name to ensure there is no conflict between your environments.
    # This is mainly for the benefit of your development and test environments.
    # Uncomment the line below if you want to disable this behaviour in production.
    #
    # config.prepend_environment = !Rails.env.production?
  
    # When using PostgreSQL schemas, the database dump will be namespaced, and
    # apartment will substitute the default namespace (usually public) with the
    # name of the new tenant when creating a new tenant. Some items must maintain
    # a reference to the default namespace (ie public) - for instance, a default
    # uuid generation. Uncomment the line below to create a list of namespaced
    # items in the schema dump that should *not* have their namespace replaced by
    # the new tenant
    #
    # config.pg_excluded_names = ["uuid_generate_v4"]
  end
  
  # Setup a custom Tenant switching middleware. The Proc should return the name of the Tenant that
  # you want to switch to.
  # Rails.application.config.middleware.use Apartment::Elevators::Generic, lambda { |request|
  #   request.host.split('.').first
  # }
  
  # Rails.application.config.middleware.use Apartment::Elevators::Domain
  Rails.application.config.middleware.use Apartment::Elevators::Subdomain
  # Rails.application.config.middleware.use Apartment::Elevators::FirstSubdomain
  # Rails.application.config.middleware.use Apartment::Elevators::Host
  </code></pre>
  
  <p>Let me know if there's any other relevant code I need to add</p>