Update README

README.md

@@ -1,6 +1,16 @@
-GCC Explorer Image
+Compiler Explorer Image
 ------------------
 
-Setup scripts to turn an Amazon EC2 instance into a GCC Explorer node.
+A whole bag of scripts and Dockerfiles and AWS config to run [Compiler Explorer](https://gcc.godbolt.org).
+
+Of most use to the casual observer is probably the code in `update_compilers` - scripts to install all the
+Compiler Explorer compilers to `/opt/compiler-explorer`. In particular, the open source compilers can be
+installed by anyone by running:
+
+```bash
+$ ./update_compilers/install_compilers.sh
+```
+
+This will grab all the open source compilers and put them in `/opt/compiler-explorer` (which must be writable by
+the current user).  To get the beta and nightly-built latest compilers, add the parameter `nightly` to the script.
 
-And a bunch of other stuff for Matt Godbolt's open source projects too.