Add contributor covenant

Closes gh-4914

CODE_OF_CONDUCT.adoc

+= Contributor Code of Conduct
+
+As contributors and maintainers of this project, and in the interest of fostering an open
+and welcoming community, we pledge to respect all people who contribute through reporting
+issues, posting feature requests, updating documentation, submitting pull requests or
+patches, and other activities.
+
+We are committed to making participation in this project a harassment-free experience for
+everyone, regardless of level of experience, gender, gender identity and expression,
+sexual orientation, disability, personal appearance, body size, race, ethnicity, age,
+religion, or nationality.
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery
+* Personal attacks
+* Trolling or insulting/derogatory comments
+* Public or private harassment
+* Publishing other's private information, such as physical or electronic addresses,
+  without explicit permission
+* Other unethical or unprofessional conduct
+
+Project maintainers have the right and responsibility to remove, edit, or reject comments,
+commits, code, wiki edits, issues, and other contributions that are not aligned to this
+Code of Conduct, or to ban temporarily or permanently any contributor for other behaviors
+that they deem inappropriate, threatening, offensive, or harmful.
+
+By adopting this Code of Conduct, project maintainers commit themselves to fairly and
+consistently applying these principles to every aspect of managing this project. Project
+maintainers who do not follow or enforce the Code of Conduct may be permanently removed
+from the project team.
+
+This Code of Conduct applies both within project spaces and in public spaces when an
+individual is representing the project or its community.
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by
+contacting a project maintainer at spring-code-of-conduct@pivotal.io . All complaints will
+be reviewed and investigated and will result in a response that is deemed necessary and
+appropriate to the circumstances. Maintainers are obligated to maintain confidentiality
+with regard to the reporter of an incident.
+
+This Code of Conduct is adapted from the
+http://contributor-covenant.org[Contributor Covenant], version 1.3.0, available at
+http://contributor-covenant.org/version/1/3/0/[contributor-covenant.org/version/1/3/0/]

CONTRIBUTING.adoc

@@ -5,6 +5,13 @@ something, or simply want to hack on the code this document should help you get
 
 
 
+== Code of Conduct
+This project adheres to the Contributor Covenant link:CODE_OF_CONDUCT.adoc[code of
+conduct]. By participating, you  are expected to uphold this code. Please report
+unacceptable behavior to spring-code-of-conduct@pivotal.io.
+
+
+
 == Using GitHub issues
 We use GitHub issues to track bugs and enhancements. If you have a general usage question
 please ask on http://stackoverflow.com[Stack Overflow]. The Spring Boot team and the