Merge pull request #67 from bartoszpietrzak1994/documentation-update

Documentation update

Author: Zales0123

README.md

@@ -10,6 +10,23 @@
 
 <p align="center">This plugin provides basic refunds functionality for Sylius application.</p>
 
+![Screenshot showing order's refund section](docs/refunds.png)
+
+![Screenshot showing order's credit memos and refund payments](docs/credit_memo.png)
+
+## Business value
+
+In contrast to basic Refund functionality delivered by core Sylius bundles, Refund Plugin offers much wider range of 
+possibilities and business scenarios.
+
+Once an Order is paid, an Administrator is able to access Refunds section of a given Order and perform a Refund
+of chosen items or shipments. What's more, if a more detailed scenario occurs, an Administrator is able to refund an item
+partially.
+
+From Administrator's point of view, every Refund request results in creating two entities: 
+* Credit Memo - a document representing a list of refunded items (downloadable and sent to Customer via .pdf file)
+* Refund Payment - entity representing payment in favour of the Customer
+
 ## Installation
 
 1. Require plugin with composer:
@@ -52,3 +69,26 @@ to your migrations directory and run `bin/console doctrine:migrations:migrate`
 
 7. Copy templates from `vendor/sylius/refund-plugin/src/Resources/views/SyliusAdminBundle/`
 to `app/Resources/SyliusAdminBundle/views/`
+
+## Extension points
+
+Refund Plugin is strongly based on both commands and events. Let's take RefundUnitsAction as an example. The whole
+process consists of following steps:
+
+* Getting data from request
+* Create a Command and fill it with data
+* Dispatch Command
+* Handle Command
+* Fire Event
+* Catch Event in Listener class
+
+Using command pattern and events make each step independent which means that providing custom implementation of given
+part of refunding process doesn't affect any other step.
+
+Apart from Events and Commands Refund Plugin is also based on mechanisms derived from core Sylius bundles such as:
+
+* [Resources](https://docs.sylius.com/en/1.2/components_and_bundles/components/Resource/index.html)
+* [Grids](https://docs.sylius.com/en/1.2/components_and_bundles/bundles/SyliusGridBundle/index.html)
+* [State Machine](https://docs.sylius.com/en/1.2/book/architecture/state_machine.html)
+
+Configuration of all elements mentioned above can be found and customized in `config.yml` file.