ALTER TABLE
	user_warrens
ADD COLUMN 
	can_list_shares BOOLEAN NOT NULL DEFAULT false,
ADD COLUMN 
	can_create_shares BOOLEAN NOT NULL DEFAULT false,
ADD COLUMN 
	can_modify_shares BOOLEAN NOT NULL DEFAULT false,
ADD COLUMN 
	can_delete_shares BOOLEAN NOT NULL DEFAULT false;

ALTER TABLE
	user_warrens
ALTER COLUMN
	can_list_shares DROP DEFAULT,
ALTER COLUMN
	can_create_shares DROP DEFAULT,
ALTER COLUMN
	can_modify_shares DROP DEFAULT,
ALTER COLUMN
	can_delete_shares DROP DEFAULT;