Ruby on Rails

I am trying to establish the following relation, but no joy!

Can someone please tell me how should I do this. 

Thanks.

Luis

#Sched attributes:
#id
#...
#  pcp_id        :integer
#  admitingMd_id :integer


class Sched < ActiveRecord::Base
  belongs_to :admitingMd, :class_name => "Pcp", :foreign_key => ":admitingMd_id"

#PCP attributes

#id
#...
class Pcp < ActiveRecord::Base
    has_many :scheds
    has_many :admitingMd, :primary_key => "admitingMd_id", :foreing_key => "admitingMd_id", :class_name => "Sched"

ArgumentError - Unknown key: :foreing_key. Valid keys are: :class_name, :anonymous_class, :foreign_key, :validate, :autosave, :table_name, :before_add, :after_add, :before_remove, :after_remove, :extend, :primary_key, :dependent, :as, :through, :source, :source_type, :inverse_of, :counter_cache, :join_table, :foreign_type: