Add usage documentation. Closes #3.

README.md

@@ -8,3 +8,5 @@ This module provides a number of useful grid field components:
 * `GridFieldAddNewMultiClass` - lets the user select from a list of classes to create a new record from.
 * `GridFieldEditableColumns` - allows inline editing of records.
 * `GridFieldOrderableRows` - drag and drop re-ordering of rows.
+
+See [docs/en/index.md](docs/en/index.md) for documentation and examples.

docs/en/index.md

@@ -0,0 +1,76 @@
+Grid Field Extensions
+=====================
+
+Add Existing Search
+-------------------
+
+The `GridFieldAddExistingSearchButton` component provides a more complete solution for adding
+existing records than a basic autocomplete. It uses the search context constructed by the model
+class to provide the search form.
+
+```php
+$grid->getConfig()->addComponent(new GridFieldAddExistingSearchButton()));
+```
+
+Inline Editing
+--------------
+
+This example replaces the default data columns component with an inline editable one, and the
+default add new button with one that adds new records inline.
+
+```php
+$grid = new GridField(
+	'ExampleGrid',
+	'Example Grid',
+	$this->Items(),
+		GridFieldConfig_RecordEditor::create()
+			->removeComponentsByType('GridFieldAddNewButton')
+			->removeComponentsByType('GridFieldDataColumns')
+			->addComponent(new GridFieldEditableColumns(), 'GridFieldEditButton')
+			->addComponent(new GridFieldAddNewInlineButton())
+);
+```
+
+You can customise the form fields that are used in the grid by calling `setDisplayFields` on the
+inline editing component. By default field scaffolding will be used.
+
+```php
+$grid->getConfig()->getComponentsByType('GridFieldEditableColumns')->setDisplayFields(array(
+	'FirstField'  => function($record, $column, $grid) {
+		return new TextField($column);
+	},
+	'SecondField' => array(
+		'title' => 'Custom Title',
+		'field' => 'ReadonlyField'
+	)
+));
+```
+
+Multi Class Adding
+------------------
+
+The `GridFieldAddNewMultiClass` allows the user to select the record type to create when creating
+a new record. By default it allows them to select the model class for the grid field, or any
+subclasses. You can control the createable classes using the `setClasses` method.
+
+```php
+$grid->getConfig()
+     ->removeComponentsByType('GridFieldAddNewButton')
+     ->addComponent(new GridFieldAddNewMultiClass());
+```
+
+Orderable Rows
+--------------
+
+The `GridFieldOrderableRows` component allows drag-and-drop reordering of any list type. The field
+used to store the sort is set by passing a constructor parameter to the component, or calling
+`setSortField`. For `many_many` relationships, the sort field should normally be an extra field on
+the relationship.
+
+```php
+// Basic usage, defaults to "Sort" for the sort field.
+$grid->getConfig()->addComponent(new GridFieldOrderableRows());
+
+// Specifying the sort field.
+$grid->getConfig()->addComponent(new GridFieldOrderableRows('SortField'));
+```