Add Code of Conduct as per main repository

Author: akrabat

CODE_OF_CONDUCT.md

@@ -0,0 +1,8 @@
+# Code of Conduct
+
+The Slim Framework code of conduct is derived from the Ruby code of conduct. This document provides community guidelines for a safe, respectful, productive, and collaborative place for any person who is willing to contribute to the Slim Framework community. It applies to all “collaborative space”, which is defined as community communications channels (such as mailing lists, IRC, Slack, forums, submitted patches, commit comments, etc.). Any violations of the code of conduct may be reported by contacting one or more of the project maintainers either directly or via email to maintainers@slimframework.com.
+
+* Participants will be tolerant of opposing views.
+* Participants must ensure that their language and actions are free of personal attacks and disparaging personal remarks.
+* When interpreting the words and actions of others, participants should always assume good intentions.
+* Behaviour that the project maintainers consider to be harassment will not be tolerated.