Update CONTRIBUTING.md.

Author: alexsegura

CONTRIBUTING.md

@@ -8,12 +8,12 @@ If you want to learn more about our opinion on open source, you can read the [OS
 
 The features available for now are only those we need, but you're welcome to open an issue or pull-request if you need more.
 
-To ensure good code quality, we use our awesome tool "[coke](https://github.com/M6Web/Coke)" to check there is no coding standards violations. 
+To ensure good code quality, we use our awesome tool "[coke](https://github.com/M6Web/Coke)" to check there is no coding standards violations.
 We use [Symfony2 coding standards](https://github.com/M6Web/Symfony2-coding-standard).
 
 To execute coke, you need to install dependencies in dev mode
 ```bash
-composer install --dev
+composer install
 ```
 
 And you can launch coke
@@ -27,12 +27,12 @@ This bundle is tested with [atoum](https://github.com/atoum/atoum).
 
 To launch tests, you need to install dependencies in dev mode
 ```bash
-composer install --dev
+composer install
 ```
 
 And you can now launch tests
 ```bash
-./vendor/bin/atoum
+bin/atoum
 ```
 
 ## Pull-request