rails has_many through and Multiple databases causing SQLite::BusyException

establish_connection_model.rb

class User < ActiveRecord::Base
   establish_connection "users_#{Rails.env}" # use alternate DB
   has_many :memberships
   has_many :groups, through => :memberships
end

class Group < ActiveRecord::Base
   establish_connection "users_#{Rails.env}" # use alternate DB
   has_many :memberships
   has_many :users, :through => :memberships
end
class Membership < ActiveRecord::Base
   belongs_to :group
   belongs_to :user
   # validations stuff
   establish_connection "users_#{Rails.env}" # use alternate DB
end