Add contributing guidelines

Author: alexpozzi

.travis.yml

@@ -31,4 +31,4 @@ install: composer update --prefer-dist
 
 script:
     - vendor/bin/phpunit
-    - composer phpstan
+    - vendor/bin/phpstan analyse --ansi --no-progress

CONTRIBUTING.md

@@ -1,15 +1,85 @@
 
 # Thanks for contributing!
-:+1: First of all, thanks for contributing! The team is happy to help if you have any questions. Have a look to this contributing guide and also to the [FAQ section](https://github.com/KnpLabs/snappy/blob/master/doc/faq.md). :feet:
-The following is a set of guidelines for contributing to Snappy, which is hosted by the [KNP Labs Organization](https://github.com/KnpLabs) on GitHub. These are mostly guidelines, not rules. Use your best judgment, and feel free to propose changes to this document opening a pull request. :shipit:
+
+:+1: First of all, thanks for contributing! The team is happy to help if you
+have any questions. Have a look to this contributing guide and also to the
+[FAQ section](https://github.com/KnpLabs/snappy/blob/master/doc/faq.md). :feet:
+The following is a set of guidelines for contributing to Snappy, which is hosted
+by the [KNP Labs Organization](https://github.com/KnpLabs) on GitHub. These are
+mostly guidelines, not rules. Use your best judgment, and feel free to propose
+changes to this document opening a pull request. :shipit:
 
 ## Code of Conduct
-This project and everyone participating in it is governed by the following [Code of Conduct](https://github.com/KnpLabs/snappy/blob/master/CODE_OF_CONDUCT.md). By participating, you are expected to uphold this code.
 
-## Before adding issues
+This project and everyone participating in it is governed by the following
+[Code of Conduct](https://github.com/KnpLabs/snappy/blob/master/CODE_OF_CONDUCT.md).
+By participating, you are expected to uphold this code.
+
+## Reporting a bug
+
+#### Before submitting a bug
+- Verify that you are using the latest Snappy version;
+- Double-check the [documentation](https://github.com/KnpLabs/snappy/blob/master/README.md)
+and the [FAQ section](https://github.com/KnpLabs/snappy/blob/master/doc/faq.md)
+to see if you're not misusing the library;
+- Check if the issue is a Snappy issue and not a wkhtmltopdf issue (see [how to](#how-to-verify-if-the-issue-is-a-snappy-issue));
+- Check if the issue has already been reported. If it has and the issue is still
+open, add a comment to the existing issue instead of opening a new one.
+
+##### How to verify if the issue is a Snappy issue
+In order to verify that the issue is a Snappy issue and not a wkhtmltopdf issue,
+simply copy paste the command displayed in the error message in your command prompt.
+If the same error appears on the command line, then it's a wkhtmltopdf issue and
+you'll have more chance to resolve your issue [there](https://github.com/wkhtmltopdf/wkhtmltopdf/issues).
+
+#### How to submit a (good) bug report
+To report a Snappy bug please open a [GitHub issue](https://github.com/KnpLabs/snappy/issues)
+following the rules below.
+
+- Use a clear and descriptive title for the issue to identify the problem;
+- Describe the steps needed to reproduce the bug including a code example when
+possible;
+- Give as much detail as possible about your environment (OS, PHP version,
+Snappy configuration, ...);
+
+## Suggesting enhancements
+
+To suggest Snappy enhancements please open a [GitHub issue](https://github.com/KnpLabs/snappy/issues)
+following the rules below.
+
+- Use a clear and descriptive title for the issue to identify the problem;
+- Provide a step-by-step description of the suggested enhancement in as many
+details as possible;
+- Explain why this enhancement would be useful with one or more use cases;
+
+## Contributing to the code
+
+A pull request, is the best way to provide a bug fix or to propose enhancements to Snappy.
+
+When submitting a pull request please be sure to follow the same rules described
+above in [Reporting a bug](#reporting-a-bug) and [Suggesting enhancements](suggesting-enhancements)
+sections depending on the nature of your change.
 
-Please verify the problem is actually a snappy problem and not a **wkhtmltopdf problem**.
+> Before starting to work on a large change please open an issue to ask the
+maintainers if they are fine with it (no one likes to work for nothing!).
 
-To do so, simply copy paste the command displayed in the error message in your command prompt.  
-If the same error appears on the command line, then it's a wkhtmltopdf problem,
-and you'll have more chance to resolve your issue [there](https://github.com/wkhtmltopdf/wkhtmltopdf/issues).
+1. Fork the repository
+2. Once the repository has been forked clone it locally
+```
+git clone [email protected]:USERNAME/snappy.git
+```
+3. Create a new branch
+```
+git checkout -b BRANCH_NAME master
+```
+4. Code!!!
+5. Add/Update tests (if needed)
+6. Update documentation (if needed)
+7. Run the tests and make sure that they are passing
+```
+composer unit-tests
+composer static-analysis
+```
+8. Squash your commits
+9. Rebase your branch on master and fix merge conflicts
+10. Open the pull request

composer.json

@@ -43,7 +43,8 @@
         }
     },
     "scripts": {
-        "phpstan": "vendor/bin/phpstan analyse --ansi"
+        "unit-tests": "vendor/bin/phpunit",
+        "static-analysis": "vendor/bin/phpstan analyse --ansi"
     },
     "extra": {
         "branch-alias": {