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CONTRIBUTING.md

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+# How to contribute
+
+CakePHP loves to welcome your contributions. There are several ways to help out:
+* Create a ticket in Lighthouse, if you have found a bug
+* Write testcases for open bug tickets
+* Write patches for open bug/feature tickets, preferably with testcases included
+* Contribute to the [documentation](https://github.com/cakephp/docs)
+
+There are a few guidelines that we need contributors to follow so that we have a
+chance of keeping on top of things.
+
+## Getting Started
+
+* Make sure you have a [GitHub account](https://github.com/signup/free)
+* Submit a ticket for your issue, assuming one does not already exist.
+  * Clearly describe the issue including steps to reproduce when it is a bug.
+  * Make sure you fill in the earliest version that you know has the issue.
+* Fork the repository on GitHub.
+
+## Making Changes
+
+* Create a topic branch from where you want to base your work.
+  * This is usually the master branch
+  * Only target release branches if you are certain your fix must be on that
+    branch
+  * To quickly create a topic branch based on master; `git branch
+    master/my_contribution master` then checkout the new branch with `git
+    checkout master/my_contribution`. Better avoid working directly on the
+    `master` branch, to avoid conflicts if you pull in updates from origin.
+* Make commits of logical units.
+* Check for unnecessary whitespace with `git diff --check` before committing.
+* Use descriptive commit messages and reference the #ticket number
+* Core testcases should continue to pass. You can run tests locally or enable
+  [travis-ci](https://travis-ci.org/) for your fork, so all tests and codesniffs
+  will be executed.
+* Your work should apply the CakePHP coding standards.
+
+## Which branch to base the work
+
+* Bugfix branches will be based on master.
+* New features that are backwards compatible will be based on next minor release
+  branch.
+* New features or other non-BC changes will go in the next major release branch.
+
+## Submitting Changes
+
+* Push your changes to a topic branch in your fork of the repository.
+* Submit a pull request to the repository in the cakephp organization, with the
+  correct target branch.
+
+## Testcases and codesniffer
+
+CakePHP tests requires [PHPUnit](http://www.phpunit.de/manual/current/en/installation.html)
+3.5 or higher. To run the testcases locally use the following command:
+
+    ./lib/Cake/Console/cake test core AllTests --stderr
+
+To run the sniffs for CakePHP coding standards
+
+    phpcs -p --extensions=php --standard=CakePHP ./lib/Cake
+
+Check the [cakephp-codesniffer](https://github.com/cakephp/cakephp-codesniffer)
+repository to setup the CakePHP standard. The README contains installation info
+for the sniff and phpcs.
+
+
+# Additional Resources
+
+* [CakePHP coding standards](http://book.cakephp.org/2.0/en/contributing/cakephp-coding-conventions.html)
+* [Bug tracker](https://cakephp.lighthouseapp.com/projects/42648-cakephp)
+* [General GitHub documentation](http://help.github.com/)
+* [GitHub pull request documentation](http://help.github.com/send-pull-requests/)
+* #cakephp IRC channel on freenode.org