Rolify Table Error (user.add_role :admin Unknown Key Error)

I'm attempting to setup the rolify gem and I'm running into an issue assigning a role to a user in the console.

Here's my error:

2.2.1 :007 > user.add_role :admin
ArgumentError: Unknown key: :optional.

I'm running devise with cancancan and rolify. I'm also running the Koudoku gem for subscription payment support. I'm suspecting this error might be caused by the fact that my "subscriptions" table also has a "user_id" column. Is there anything I can do to correct this issue?

Here's my schema.

create_table "subscriptions", force: :cascade do |t|
t.string   "stripe_id"
t.integer  "plan_id"
t.string   "last_four"
t.integer  "coupon_id"
t.string   "card_type"
t.float    "current_price"
t.integer  "user_id"
t.datetime "created_at",    null: false
t.datetime "updated_at",    null: false
end

create_table "users", force: :cascade do |t|
t.string   "email",                  default: "", null: false
t.string   "encrypted_password",     default: "", null: false
t.string   "reset_password_token"
t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
t.integer  "sign_in_count",          default: 0,  null: false
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string   "current_sign_in_ip"
t.string   "last_sign_in_ip"
t.datetime "created_at",                          null: false
t.datetime "updated_at",                          null: false
t.string   "first_name"
t.string   "string"
t.string   "last_name"
end

 add_index "users", ["email"], name: "index_users_on_email", unique: true
 add_index "users", ["reset_password_token"], name:    
 "index_users_on_reset_password_token", unique: true

create_table "users_roles", id: false, force: :cascade do |t|
t.integer "user_id"
t.integer "role_id"
end

add_index "users_roles", ["user_id", "role_id"], name:   "index_users_roles_on_user_id_and_role_id"

end

Thanks.