initial readme for the app

vm/README.md

@@ -1,3 +1,20 @@
 # apptron
 
-https://github.com/tractordev/apptron
+Welcome to Apptron! This is just a tech demo right now, but Apptron is the
+**first general development environment in the browser**. Codespaces? Replit? No, 
+their development environments run in the *cloud*. Apptron runs entirely in the 
+browser.
+
+The file tree in the Explorer is the root filesystem of an Alpine Linux virtual
+machine running on this page. The Terminal has a shell open in this VM. Any 
+changes to the VM are autosaved locally every 10 seconds. This means you can 
+customize the VM to add development tools or even clone a Git repository to 
+work on.
+
+All the components for this are open source, so you could easily build your own.
+It's just a static site, so it's trivial to run and costs almost nothing.
+
+More details will be put online soon, but in the meantime you can ask questions
+or just stay up to date by sponsoring me on GitHub:
+
+https://github.com/sponsors/progrium