Added docs

Author: danielgindi

README.md

@@ -11,6 +11,9 @@ The following compression codings are supported:
 
   - deflate
   - gzip
+  - br (brotli)
+
+**Note** Brotli provides better and faster compression then gzip or deflate, but is supported only since Node.js versions v11.7.0 and v10.16.0.
 
 ## Install