Spree 2.0.0

insert_checkout_step :new_step, before: :address
# or
insert_checkout_step :new_step, after: :address```

The `remove_checkout_step` will remove just one checkout step at a time:

```ruby
remove_checkout_step :address
remove_checkout_step :delivery```

### Dash

## Minor changes

### API

#### CheckoutsController

The Spree API now has support for "checking out" an order. This API
functionality allows an existing order to be updated and advanced until
it is in the complete state.

For instance, if you have an order in the "confirm" state that you would
like to advance to the "complete" state, make the following request:

```bash
PUT /api/checkouts/ORDER_NUMBER```

For more information on using the new CheckoutsController, please see
the [Checkouts API Documentation](/api/checkouts).

#### Versioned templates

API responses can now be versioned by the [versioncake](https://github.com/bwillis/versioncake) gem. While this is not used in Spree at the moment, it is future-proofing the API.

### Core

#### Auto-rotation of images

Images will now be auto-rotated to their correct orientation based on EXIF data from the original image. All EXIF data is then stripped from the image, resulting in a smaller final image size.

<%= issue 2338 %>

#### Sample data

The sample data now exists within straight Ruby code. The previous YAML-backed
configuration was confusing and led to invalid data being inserted for sample data.

<%= commit "cc2f55a27a154c0bf9d67e1dbef3c4761c68f8b8" %>

#### Unique payment identifier

Some payment gateways require payments to have a unique identifier. To solve this problem in Spree, each payment now has an `identifier` attribute which is generated when the payment is created.

<%= issue 1998 %>
<%= commit "b543fd105c2d511cdc98f27223cd0f5b1f663e72" %>

#### Removal of `CheckoutController#state_callback`

The `state_callback` method in `CheckoutController` has been removed. Instead of this method, please use transition callbacks on the `Order.state_machine` instance instead.

#### Tracking URL for shipments

Shipping methods now have the ability to have tracking URLs. These can be used to track the shipments on external shipping providers' websites.

<%= issue 2644 %>

#### Mailers now can take IDs or model objects

To help with potential background processing of mailers, all mailer actions can now take the ID of their respective object, or the object itself.

<%= issue 2808 %>

#### SSLRequirement deprecated in favour of ForceSSL

Spree will now use the `config.force_ssl` setting of Rails to determine whether or not to use SSL.

<%= issue 2410 %>

#### MailMethod model no longer exists

The `MailMethod` model no longer exists. Instead, it is a class and all configuration is now done through that class or through `Spree::Config` settings.

<%= issue 2643 %>

## Trivial changes

Some of these changes may have made it into 1-3-stable or 1-2-stable as well. You may wish to check that branch for commits with the same message to make sure of this.

* `ShippingMethod` labels can now be overriden by overriding the `adjustment_label` method. <%= issue(2222) %>
* Promotion rules that respond to `#products` will have their products considered in promotion adjustments. <%= issue 2363 %>
* Taxons and products are now joined with a `Classification` model. <%= issue 2532 %> <%= commit "0c594923a457d2f6050c936498d31df312d6153a" %>
* Fix call to `select_month` and `select_year` <%= issue 2259 %>
* Fix issue where `params[:keyword]`, not `params[:keywords]` was acknowledged on taxons/show.html.erb. <%= issue 2258 %> <%= issue 2270 %>
* Allow overriding of a shipping address's label <%= issue 2222 %>
* Guard against false positive Jirafe conversions <%= issue 2273 %> <%= issue 2211 %> <%= issue 2157 %>
* Add first_name and last_name aliases for Addresses <%= commit "ad119f9e21af9ba6f6ada96944fc758a6144c61c" %>
* Escape JavaScript within ecommerce tracking code <%= issue 2289 %>
* Slight refactoring of how preferences are fetched from preference store <%= commit "bddc49a5cf261ca9fcee45e4234bdb076eaa3feb" %>
* Fix issue where "New State" button on country page would not link to correct country. <%= issue 2281 %>
* Order#checkout_steps will now always include complete <%= commit "5110e12127840fb9b2e22f8b4f4c4fbee594de23" %>
* Fix issue where `flash[:commerce_tracking]` was hanging around too long. <%= issue 2287 %>
* Remove colons from translations in mail templates <%= issue 2278 %>
* A payment method can now control its `auto_capture?` method. <%= issue 2304 %>
* Added a preference to display a product without a price. <%= issue 2302 %>
* Improve 'out of stock' error message. <%= issue 1821 %>
* Track IP addresses for orders, for payment gateway reasons. <%= issue 2216 %> <%= issue 2257 %>
* Use protocol-specific URL for font. <%= issue 2316 %>
* First order promotion will now work with guest users. <%= issue 2306 %>
* Always show resend button on admin order page. <%= issue 2318 %>
* Allow a shipment to be made 'ready' once order has been made 'resumed' <%= issue 2317 %>
* PerItem calculator no longer fails if a rule doesn't respond to the `products` method. <%= issue 2322 %>
* `attachment_url` can now be configured from the admin backend. <%= issue 2344 %>
* Scale and precision have been corrected in split_prices_from_variants migration. <%= issue 2358 %>
* Localize error message for email validator. <%= issue 2364 %> <%= issue 2729 %> <%= issue 2730 %>
* Remove duplicate thumbnails on products/show. <%= issue 2361 %>
* Use line item price, not variant price, in return authorization price calculation JS. <%= issue 2342 %>
* Allow for a product's description to be put to the page raw <%= issue 2323 %> <%= issue 2874 %> <%= commit "30fdf083" %>. See also <%= commit "b616d84a78e426bdeb3e8e6251aaa9ce8757996d" %> and <%= issue 2518 %>.
* Promotions can now apply to orders which were created before the promotion. <%= issue 2388 %> <%= issue 2395 %>
* Allow Address#phone validation to be overridden. <%= issue 2394 %>
* Sort properties by alphabetical order on prototype form. <%= issue 2389 %>
* Introduce datepicker_field_value for displaying datepicker field values. <%= issue 2405 %>
* The 'New Product' button now appears on the edit product page. <%= issue 2407 %>
* option values in `Variant#options_text` are now sorted in a predictable order. <%= issue 2432 %>
* link_to_cart can now be used outside of Spree contexts. <%= issue 2441 %>
* Promotion adjustments will now be removed on orders which are not complete when the promotion is deleted. <%= issue 1046 %> <%= issue 2453 %>
* Adjustments are now displayed on the orders/show template. <%= issue 2449 %>
* Variant images are displayed in place of product images in admin/images <%= issue 2228 %>
* Product properties are now sortable. <%= issue 2464 %>
* Returned items can now be re-shipped. <%= issue 2475 %>
* LogEntry records are now saved for failed payments <%= issue 1767 %>
* Show full address in order confirmation <%= issue 2136 %> <%= issue 2511 %>
* Retrieve a list of variants from an order by calling `Order#variants`. <%= issue 2195 %>
* Fix group_by_products_id sometimes not being available as a scope. <%= issue 1247 %>
* Allow `meta_description` on `Spree::Product` to be as long as `text` will allow, rather than `string`. <%= issue 2611 %>
* Fix currency display issues when using Euro. <%= issue 2634 %>
* Fix issue where orders would become "locked" when initial payment had failed. <%= issue 2616 %> <%= issue 2570 %> <%= issue 2678 %> <%= issue 2585 %> <%= issue 2652 %>
* Check for unprocessed payments before transitioning to complete state <%= issue 2694 %>
* Added check to prevent skipping of checkout steps. <%= issue 2280 %>
* Improve the look of the coupon code on the checkout. <%= issue 2720 %>
* Admin tabs are now only displayed if user is authorized to see them. <%= issue 2626 %>
* Reduce minimum characters required for variant autocomplete <%= issue 2774 %>
* Added helper methods to shipment to calculate shipment item and total costs <%= issue 2843 %>
* Allow product scopes to be added to from an extension <%= issue 2608 %>
* Fix routing error caused by routing-filter and previous ghetto implementation of taxon autocomplete. <%= issue 2248 %>
* ActionMailer settings will no longer be re-configured if they're already set. <%= issue 2855 %>
* Fix issue where tax calculator computed taxes incorrectly for non-VAT taxes. <%= issue 2870 %>
* The coupon code field is now hidden when there are no possible coupon codes. <%= issue 2835 %>
* The `position` attribute for variants is now computed once the variant is saved. <%= issue 2744 %>
* Account for situation where `current_order` might return `nil` in an `OrdersController#update` call. <%= issue 2750 %>
* Fix case where ActiveMerchant would incorrectly process currencies without 2 decimal places. <%= issue 2930 %>
* Add US military states to default states. <%= issue 2769 %>
* Allow for specially overridden attributes for line items in the API. <%= issue 2916 %>
* Transition order as far to complete as it will go after editing customer details. <%= issue 2950 %> <%= issue 2433 %>
* Fix issue where going back a step in a cart could cause a `undefined method run_callbacks` error to be raised. <%= issue 2959 %> <%= issue 2921 %>
* Use DISTINCT ON to make product `in_taxon` scope really distinct in PostgreSQL <%= issue 2851 %>
* Run order update hooks when order is finalized too <%= issue 2986 %>