user = User.find_by_uuid!(params[:uuid])

name = hash.fetch('name')

case action
  when :upgrade then # ...
  when :downgrade then # ...
  else raise ArgumentError
end

user.save!

create_table "subscriptions" do
  t.string    "plan_code", null: false
  t.integer   "account_id", null: false
  t.timestamp "deleted_at"
end

add_index "subscriptions", [:account_id, :deleted_at], unique: true
add_foreign_key "subscriptions", "accounts"