Add contributing instructions

See #147

Signed-off-by: Michal Čihař <[email protected]>

Author: nijel

CONTRIBUTING.md

@@ -0,0 +1,42 @@
+# Contributing to SQL Parser
+
+## Reporting issues
+
+Our issue tracker is hosted at GitHub:
+
+https://github.com/phpmyadmin/sql-parser/issues
+
+Please search for existing issues before reporting new ones.
+
+## Working with Git checkout
+
+The dependencies are managed by Composer, to get them all installed (or update
+on consequent runs) do:
+
+```
+composer update
+```
+
+## Submitting patches
+
+Please submit your patches using GitHub pull requests, this allows us to review
+them and to run automated tests on the code.
+
+## Coding standards
+
+We do follow PSR-1 and PSR-2 coding standards. 
+
+You can use php-cs-fixer to fix the code to match our expectations:
+
+```
+php-cs-fixer fix .
+```
+
+## Testsuite
+
+Our code comes with quite comprehensive testsuite, it is automatically executed
+on every commit and pull request, you can also run it locally:
+
+```
+./vendor/bin/phpunit -c phpunit.xml
+```