First README draft; needs additions and improvement

Author: jstrieb

README.md

@@ -0,0 +1,68 @@
+# Introduction
+
+Create a collaborative environment inside GitHub Actions for solving CTF
+problems. Conveniently save progress with git.
+
+# Quick start
+
+- Create a repo from the template ("Use this template")
+- Navigate to the "Actions" tab
+- Choose the correct workflow on the left ("Run Collaborative CTF Environment")
+- Run it using the button in the top right ("Run workflow")
+  - Optionally enter a webhook that it can send POST data to
+- View the output; wait for it to print and/or send the tmate connection info
+- SSH in or connect from the Web
+
+# Graphical
+
+**Don't use the graphical workflow unless absolutely necessary!**
+
+- Sign up for ngrok and get an authentication token
+- Run the workflow and pass in the ngrok authentication token
+- Wait for ngrok to run, and look in your ngrok dashboard for the server and
+  port to connect to
+- Connect using an [RDP](https://en.wikipedia.org/wiki/Remote_Desktop_Protocol)
+  client if using the graphical workflow
+  - Username `runner`
+  - Password `password`
+  - There is a default RDP client installed on Windows
+  - For Linux [Remmina](https://remmina.org/how-to-install-remmina/)
+
+# Be a Good Citizen
+
+This project uses generously-offered, free resources in a way that was likely
+not intended by GitHub. Please do not abuse them.
+
+I claim no responsibility for how you use this project. Based on my reading of
+GitHub's:
+
+- [Terms of
+  Service](https://docs.github.com/en/free-pro-team@latest/github/site-policy/github-terms-of-service#the-github-terms-of-service)
+- [Acceptable Use
+  Policy](https://docs.github.com/en/free-pro-team@latest/github/site-policy/github-acceptable-use-policies)
+- and [Actions Usage
+  Policy](https://docs.github.com/en/free-pro-team@latest/github/site-policy/github-additional-product-terms)
+
+I have concluded that using this Actions workflow to do productive work,
+particularly if you don't have the ability to run a Linux computer of your own,
+is probably permissible if done in good faith, and with an effort made to
+reduce excessive resource consumption. For example, don't use the graphical
+workflows unless absolutely necessary, because they are considerably more
+resource intensive to set up and run.
+
+That being said, I may be reading the policies wrong, and GitHub has the right
+to change them at any time. In particular, if this is abused, it is likely that
+its use will be limited by GitHub. **If you like it, don't ruin it for
+others.**
+
+Users get [3,000 minutes of private Actions
+time](https://docs.github.com/en/free-pro-team@latest/actions/reference/usage-limits-billing-and-administration#usage-limits)
+per month per user. Check your own usage
+[here](https://github.com/settings/billing).
+
+# Acknowledgments
+
+This project makes use of several great software packages that have made their
+services available for free:
+- [tmate.io](https://tmate.io/)
+- [ngrok](https://ngrok.com)