ROR: Foreign key/model relationship confusion - is this possible?

I've got a Rails project with these model relationships:

class Business < ActiveRecord::Base
  has_many :customers, :dependent => :destroy
  has_many :locations, :dependent => :destroy
end

class Customer < ActiveRecord::Base
  belongs_to :business
  has_one :calendar, :dependent => :destroy
end

class Calendar < ActiveRecord::Base
  belongs_to :customer
  has_many :events, :dependent => :destroy
end

class Event < ActiveRecord::Base
  belongs_to :calendar
  has_one :location
end

I have just created a model 'location.rb' which I have integrated into the business and event model relationships.

My question is split in 2:

1. How can I write my location relationship so that it belongs to a business but can still be "owned"(used) by an event?

The reason I am asking this is because I need to be able to have an 'location_id' column in my events table as a foreign key.

Here is my location.rb so far:

class Location < ActiveRecord::Base
  belongs_to :business
end

2. If 1) is possible, how can my events migration table create the location_id foreign key?

Here is my current migration table for events:

class CreateEvents < ActiveRecord::Migration
  def change
    create_table :events do |t|

      t.timestamps
      t.references :calendar, foreign_key: true
      #t.references :location, foreign_key: true

      t.string :name
      t.string :description
      t.date :day
      t.integer :event_id
      t.datetime :starts_at
      t.datetime :ends_at
end
end
end

I have commented out my attempt, but I'm not sure this would work without some kind of relationship linking the two?