Adjust Refund docs, add link to gitbook docs and remove it from here (#478)

| Q               | A
| --------------- | -----
| Branch?         | 2.0 (new features)
| Bug fix?        | no
| New feature?    | no

Author: GSadee

README.md

@@ -16,132 +16,22 @@
 
 <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](docs/credit_memos.png)
+## Documentation
 
-![Screenshot showing credit memo details page](docs/credit_memo.png)
+📖 Full documentation is available here:
+👉 [Refund Plugin Documentation](https://docs.sylius.com/refund-plugin)
 
-## 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
-
-#### Beware!
-
-This installation instruction assumes that you're using Symfony Flex. If you don't, take a look at the
-[legacy installation instruction](docs/legacy_installation.md). However, we strongly encourage you to use
-Symfony Flex, it's much quicker!
-
-1. Require plugin with composer:
-
-    ```bash
-    composer require sylius/refund-plugin
-    ```
-
-    > Remember to allow community recipes with `composer config extra.symfony.allow-contrib true` or during plugin installation process
-
-1. Apply migrations to your database:
-
-    ```bash
-    bin/console doctrine:migrations:migrate
-    ```
-
-1. Run `yarn encore dev` or `yarn encore production`
-
-1. Default configuration assumes enabled PDF file generator. If you don't want to use that feature change your app configuration:
-
-   ```yaml
-   # config/packages/sylius_refund.yaml
-   sylius_refund:
-      pdf_generator:
-         enabled: false
-   ```
-
-   Otherwise, check if you have wkhtmltopdf binary. If not, you can download it [here](https://wkhtmltopdf.org/downloads.html).
-
-   In case wkhtmltopdf is not located in `/usr/local/bin/wkhtmltopdf` modify the `WKHTMLTOPDF_PATH` environment variable in the `.env` file:
-   
-   ```
-   WKHTMLTOPDF_PATH=/usr/local/bin/wkhtmltopdf # Change this! :)
-   ```
-
-## 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.
-
-## Payment requirements
-
-By default to refund your order, you need to have at least one available payment method configured with `offline` gateway.
-In case your custom refund logic allows a different type of gateway (for example `stripe`), you should modify the specific parameter,
-as shown below:
-
-```yaml
-# config/services.yaml
- 
-parameters:
-    sylius_refund.supported_gateways:
-        - offline
-        - stripe
-```
-
-Online refund logic should be implemented if you need it.
-As the first try for the possible customization, you can check out `Sylius\RefundPlugin\Event\UnitsRefunded` event.
-
-## Post-refunding process
-
-After units are refunded, there are multiple other processes that should be triggered. By default, after units refund, there should be **CreditMemo** and
-**RefundPayment** generated. As they're strictly coupled with each other, **RefundPayment** is always created after the **CreditMemo**. Moreover, if **RefundPayment**
-fails, related **CreditMemo** should not be created as well.
-
-`Sylius\RefundPlugin\ProcessManager\UnitsRefundedProcessManager` service facilitates the whole process. If you want to add one or more steps to it, you should create
-a service implementing `Sylius\RefundPlugin\ProcessManager\UnitsRefundedProcessStepInterface`, and register if with proper tag:
-
-```yaml
-App\ProcessManager\CustomAfterRefundProcessManager:
-    tags:
-        - { name: sylius_refund.units_refunded.process_step, priority: 0 }
-```
+## Security issues
 
-Tagged services would be executed according to their priority (descending). 
+If you think that you have found a security issue, please do not use the issue tracker and do not post it publicly.
+Instead, all security issues must be sent to `security@sylius.com`.
 
-## Supported branches
+## Community
 
-* `1.4` (v1.4.*) - security fixes
-* `1.5` (v1.5.*) - bug fixes, improvements
-* `1.6` (v1.6.*) - new features
-* `2.0` (v2.0.*) - new features, removing deprecations, BC breaks
+For online communication, we invite you to chat with us and other users on [Sylius Slack](https://sylius.com/slack).
 
-## Security issues
+## License
 
-If you think that you have found a security issue, please do not use the issue tracker and do not post it publicly.
-Instead, all security issues must be sent to `security@sylius.com`.
+This plugin is released under the [MIT License](LICENSE).