Add override doc.

Resources/doc/override.md

@@ -0,0 +1,41 @@
+Override
+========
+
+## Configuration
+
+```yaml
+darvin_utils:
+    override:
+        DarvinECommerceBundle:
+            order:
+                entities:
+                    - Order\Order
+                templates:
+                    - admin/order
+                    - order
+            product:
+                entities:
+                    - Product
+                templates:
+                    - product
+```
+
+## Usage
+
+### Override all functionality
+
+```shell script
+$ bin/console darvin:utils:override product 
+```
+
+### Override specific functionality
+
+```shell script
+$ bin/console darvin:utils:override product admin
+```
+
+### Specify bundle if subject name is ambiguous
+
+```shell script
+$ bin/console darvin:utils:override product -b DarvinECommerceBundle
+```