Create CODE_OF_CONDUCT.md (#33)

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~~Defaulting to the [Contributor Covenant
](https://www.contributor-covenant.org/) for now.~~

Defaulting to [Hyper’s minimalistic
CoC](https://github.com/hyperium/hyper/blob/master/docs/CODE_OF_CONDUCT.md)
for now.

CODE_OF_CONDUCT.md

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+# Code of Conduct
+
+## Be Kind
+
+- Don't be mean.
+- Insulting anyone is prohibited.
+- Harassment of any kind is prohibited.
+- If another person feels uncomfortable with your remarks, stop it.
+- If a moderator deems your comment or conduct as inappropriate, stop it.
+- Disagreeing is fine, but keep it to technical arguments. Never attack the person.
+- Give the benefit of the doubt. Assume good intentions.
+- Show empathy. There are 3 interpretations to any message: what we thought, what we said, and what they understand.
+- This does mean we exclude people who are not kind. We are happy to make that sacrifice.
+
+## Or Else
+
+- Violations of the Code of Conduct will result in 1 warning.
+- If the violation is major, a moderator may just ban immediately.
+- If a warning has already been given, a moderator will ban the offender.
+- There is no process for appealing a ban.
+- Any violations can be reported to [email protected]