Add Code of Conduct (#1048)

The tutorials repo was previously missing a code of conduct file for the
repository. Since IBM Quantum has rewritten the code of conduct to put in
place a stronger enforcement process and tighten up the language and the
other qiskit repos were going through and updating the contents of their
CODE_OF_CONDUCT.md. This commit takes the opportunity to add the missing
CODE_OF_CONDUCT.md with this new version.

Related to Qiskit/qiskit#1057

Author: mtreinish

CODE_OF_CONDUCT.md

@@ -0,0 +1,113 @@
+# Code of Conduct
+
+## Our Pledge
+
+The Qiskit Community is dedicated to our values of treating every individual
+with respect and dignity. In the interest of fostering an open and welcoming
+environment, all participants, including attendees, speakers, sponsors,
+volunteers, online contributors, and IBM employees are expected to show
+courtesy for each other and our community by creating a harassment-free
+experience for everyone, regardless of age, personal appearance, disability,
+ethnicity, gender identity and expression, body size, level of experience,
+nationality, race, religion, caste, or sexual identity and orientation.
+Expected behavior applies to both online and offline engagement within the
+Qiskit Community.
+
+## Scope
+
+The purpose of this Code of Conduct is to define and enforce the values and
+conduct of contributors and participants in the Qiskit open source community.
+The Code of Conduct applies both within project spaces and in public spaces
+when an individual is engaging with the Qiskit open source community. Examples
+include attending a Qiskit event, contributing to online projects, commentary
+on Slack, or representing a project or community, including using an official
+project e-mail address, posting via an official social media account, or
+acting as an appointed representative at an online or offline event.
+Representation of a project may be further defined and clarified by project
+maintainers.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+- Using welcoming and inclusive language
+- Being respectful of differing viewpoints, experiences, and cultures
+- Gracefully accepting constructive criticism
+- Focusing on what is best for the community
+- Showing empathy towards other community members
+- Being mindful of your surroundings and your fellow participants and listening
+  to others
+- Valuing the contributions of all participants
+- Engaging in collaboration before conflict
+- Pointing out unintentionally racist, sexist, casteist, or biased comments and
+  jokes made by community members when they happen
+
+Examples of unacceptable behavior by participants, even when presented as
+"ironic" or "joking," include:
+
+- The use of sexualized language or imagery and unwelcome physical contact,
+  sexual attention, or advances
+- Trolling, insulting/derogatory comments, and personal or political attacks
+- Public or private harassment, including offensive or degrading language
+- Publishing others' private information, such as a physical or electronic
+  address, without explicit permission. This includes any sort of "outing" of
+  any aspect of someone's identity without their consent.
+- "Doxxing," Publishing screenshots or quotes, especially from identity slack
+  channels, private chat, or public events, without all quoted users' explicit
+  consent.
+- Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Responsibilities & Enforcement
+
+The entire Qiskit community is responsible for upholding the terms of the Code
+of Conduct in Qiskit Community events and spaces and reporting violations if
+they see them. The internal Qiskit team at IBM is ultimately responsible for
+clarifying the standards of acceptable behavior and enforcement, and is expected
+to take appropriate and fair corrective action in response to any instances of
+unacceptable behavior.
+
+If a participant or contributor engages in negative or harmful behavior, IBM
+will take any action they deem appropriate, including but not limited to
+issuing warnings, expulsion from an event with no refund, deleting comments,
+permanent banning from future events or online community, or calling local law
+enforcement. IBM has 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 temporarily or permanently ban any
+contributor or participant for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+If you see a Code of Conduct violation:
+
+1. If you feel comfortable, let the person know that what they did is not
+   appropriate and ask them to stop and/or edit or delete their message(s) or
+   comment(s).
+2. If the person does not immediately stop the behavior or correct the issue,
+   or if you're uncomfortable speaking up, flag a moderator and, if appropriate,
+   fill out the anonymous
+   [Code of Conduct violation form](https://airtable.com/shrl5mEF4Eun1aIDm).
+3. The Qiskit Community will open an investigation upon receiving your form
+   entry. When reporting, please include any relevant details, links,
+   screenshots, context, or other information that may be used to better
+   understand and resolve the situation.
+4. If the code of conduct violation occurs at an event and requires immediate
+   response or contains a concern about an individual attending an upcoming
+   event, contact the event's on-call Code of Conduct point of contact listed
+   in the event specific code of conduct document. If you don't feel comfortable
+   speaking to the point of contact in person, fill out a Code of Conduct
+   violation form entry and include the details of the event so that the Code of
+   Conduct enforcement board can contact the event's on-call Code of Conduct
+   point of contact.
+5. If an IBM employee witnesses a Code of Conduct violation at any time, such as
+   at events, in a Slack channel, or open source forums, it is their
+   responsibility to file a Code of Conduct violation report.
+
+This Code of Conduct does not supersede existing IBM corporate policies, such as
+the IBM Business Conduct Guidelines and IBM Business Partner Code of Conduct.
+IBM employees must follow IBM's Business Conduct Guidelines. IBM's business
+partners must follow the IBM Business Partner Code of Conduct. IBM employees
+concerned with a fellow IBMer's behavior should follow IBM's own internal HR
+reporting protocols, which include engaging the offending IBMer's manager and
+involving IBM Concerns and Appeals. IBM employees concerned with an IBM
+business partner's behavior should notify tellibm@us.ibm.com.