#13 add DatabaseUpdaterTask documentation

Author: Xavier Marchegay

docs/reference/tasks/database_updater_task.md

@@ -0,0 +1,44 @@
+DatabaseReaderTask
+==================
+
+Writes data to a database.
+
+Task reference
+--------------
+
+* **Service**: `CleverAge\DoctrineProcessBundle\Task\Database\DatabaseUpdaterTask`
+
+Accepted inputs
+---------------
+
+Input can be used as the query params if needed
+
+Possible outputs
+----------------
+
+Iterate on an entity list returned by a sql query.
+
+Options
+-------
+
+| Code              | Type               | Required | Default   | Description                                    |
+|-------------------|--------------------|:--------:|-----------|------------------------------------------------|
+| `connection`      | `string`           |          | `null`    | Doctrine connection (default if not specified) |
+| `sql`             | `string`           |  **X**   | `null`    | Query to execute                               |
+| `input_as_params` | `bool`             |          | `false`   | Use the input as params                        |
+| `params`          | `array`            |          | `[]`      | Query params                                   |
+| `types`           | `array`            |          | `[]`      | Query params types                             |
+
+Example
+-------
+
+```yaml
+entry:
+  service: '@CleverAge\DoctrineProcessBundle\Task\Database\DatabaseUpdaterTask'
+  options:
+    sql: 'update author set firstname = :firstname, lastname = :lastname'
+    input_as_params: false
+    params:
+      firstname: 'Pascal'
+      lastname: 'Dupont'
+```