Added code manifesto as code of conduct

CONDUCT.md

@@ -0,0 +1,43 @@
+# Contributor Code of Conduct
+
+The Zend Framework project adheres to [The Code Manifesto](http://codemanifesto.com)
+as its guidelines for contributor interactions.
+
+## The Code Manifesto
+
+We want to work in an ecosystem that empowers developers to reach their
+potential — one that encourages growth and effective collaboration. A space that
+is safe for all.
+
+A space such as this benefits everyone that participates in it. It encourages
+new developers to enter our field. It is through discussion and collaboration
+that we grow, and through growth that we improve.
+
+In the effort to create such a place, we hold to these values:
+
+1. **Discrimination limits us.** This includes discrimination on the basis of
+   race, gender, sexual orientation, gender identity, age, nationality, technology
+   and any other arbitrary exclusion of a group of people.
+2. **Boundaries honor us.** Your comfort levels are not everyone’s comfort
+   levels. Remember that, and if brought to your attention, heed it.
+3. **We are our biggest assets.** None of us were born masters of our trade.
+   Each of us has been helped along the way. Return that favor, when and where
+   you can.
+4. **We are resources for the future.** As an extension of #3, share what you
+   know. Make yourself a resource to help those that come after you.
+5. **Respect defines us.** Treat others as you wish to be treated. Make your
+   discussions, criticisms and debates from a position of respectfulness. Ask
+   yourself, is it true? Is it necessary? Is it constructive? Anything less is
+   unacceptable.
+6. **Reactions require grace.** Angry responses are valid, but abusive language
+   and vindictive actions are toxic. When something happens that offends you,
+   handle it assertively, but be respectful. Escalate reasonably, and try to
+   allow the offender an opportunity to explain themselves, and possibly correct
+   the issue.
+7. **Opinions are just that: opinions.** Each and every one of us, due to our
+   background and upbringing, have varying opinions. The fact of the matter, is
+   that is perfectly acceptable. Remember this: if you respect your own
+   opinions, you should respect the opinions of others.
+8. **To err is human.** You might not intend it, but mistakes do happen and
+   contribute to build experience. Tolerate honest mistakes, and don't hesitate
+   to apologize if you make one yourself.

CONTRIBUTING.md

@@ -227,3 +227,4 @@ repository, we suggest doing some cleanup of these branches.
    ```console
    $ git push {username} :<branchname>
    ```
+\n\n## Conduct\n\nPlease see our [CONDUCT.md](CONDUCT.md) to understand expected behavior when interacting with others in the project.