add compiler support document - closes #2839

doc/design/compiler-environment-support.md

@@ -0,0 +1,15 @@
+# Compiler environment support
+
+The Babel compiler is **only** supported in these environments:
+
+ - Modern browsers such as Chrome, Firefox, Safari, Edge etc.
+ - Node 0.10+
+
+This means that notably Babel does not support the following environments:
+
+ - Rhino
+ - Nashorn
+ - Internet Explorer
+ - ...
+
+**NOTE:** Compiler support does not dictate the runtime requirements of compiled code.