Clarified contribution instructions

.github/CONTRIBUTING.md

@@ -2,7 +2,7 @@
 
 Thank you for considering contributing to Deployer. Please make sure to read the following sections if you plan on submitting new issues or pull requests.
 
-## Bug
+## Reporting bugs
 
 In order for us to provide you with help as fast as possible, please make sure to include the following when reporting bugs.
 
@@ -12,19 +12,25 @@ In order for us to provide you with help as fast as possible, please make sure t
 * Content of `deploy.php`
 * Output log with enabled option for verbose output `-vvv`
 
-## New features
+Please check [existing issues](https://github.com/deployphp/deployer/issues) before opening a new issue, to prevent duplication. You can [open a new issue here](https://github.com/deployphp/deployer/issues/new).
 
-All code contributions must go through a pull request and approved by a core developer before being merged.
-This is to ensure proper review of all the code.
+## Contributing code
 
 Fork the project, create a feature branch, and send a pull request.
 
-To ensure a consistent code base, you should make sure the code follows
-the [PSR-1](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-1-basic-coding-standard.md).
-
 If you would like to help take a look at the [list of issues](https://github.com/deployphp/deployer/issues).
 
+### Code quality
+
+To ensure a consistent code base, please make sure the code follows
+the [PSR-1 standard](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-1-basic-coding-standard.md).
+
+### Update the changelog
+
+Before submitting code make sure to add notes about your changes to [CHANGELOG.md](https://github.com/deployphp/deployer/blob/master/CHANGELOG.md).
+
+To ensure consistent formatting and avoid test failures it's best to do this from the command line. From the project root first install composer dependencies (`composer install`), then run `php bin/changelog`.
 
-## Make a Pull Request
+### Submit a pull request
 
-Add notes about your changes to [CHANGELOG.md](https://github.com/deployphp/deployer/blob/master/CHANGELOG.md).
+All code contributions must go through a pull request and be approved by a core developer before being merged. This is to ensure proper review of all the code.

.github/PULL_REQUEST_TEMPLATE.md

@@ -6,9 +6,4 @@
 | Deprecations? | Yes or No
 | Fixed tickets | N/A or xx
 
-> Do not forget to add notes about your changes to CHANGELOG.md
->
-> Easiest way to do it, by running next command:
->
->     php bin/changelog
->
+> Do not forget to add notes about your changes to CHANGELOG.md. A command line tool has been included to make this easy, see [CONTRIBUTING.md](CONTRIBUTING.md#update-the-changelog) for details.