Update readme

Author: joubertredrat

README.md

@@ -1 +1,34 @@
-# entity-datetime
+# Entity datetime
+
+Trait for easy manage useful datetime in entities.
+
+#### Usage
+
+##### With Doctrine
+
+1 - Add trait in your Entity
+
+```php
+<?php
+
+use RedRat\Entity\DateTimeTrait;
+
+class Foo
+{
+    use DateTimeTrait;
+}
+```
+
+2 - Set `lifecycleCallbacks` in your Doctrine configuration, like example below:
+
+```yaml
+    lifecycleCallbacks:
+        prePersist: [ forgeCreatedAt ]
+        preUpdate: [ forgeUpdatedAt ]
+```
+
+Note: More about lifecycle callbacks in Doctrine [documentation](https://www.doctrine-project.org/projects/doctrine-orm/en/2.7/reference/events.html#lifecycle-callbacks).
+
+#### TODO
+
+* API documentation.