add a description for dictionaries in readme

README.md

@@ -148,6 +148,13 @@ Vendoring with modules is not yet supported. A `vendor` directory will be ignore
 Note that while modules are used to prepare the build, the final instrumented build is still done in GOPATH mode.
 For most modules, this should not matter.
 
+## Fuzzing dictionaries
+
+Go-fuzz supports user-defined dictionaries containing tokens or interesting byte sequences. Dictionaries replace the 
+low-signal token list that is automatically generated by go-fuzz with a high-signal token list. 
+Use `-dict DICTIONARY_FILE` to provide a dictionary. The dictionary syntax is the same as AFL/Libfuzzer. 
+See [AFL Dictionaries](https://github.com/google/AFL/blob/master/dictionaries/README.dictionaries) for more information.
+
 ## libFuzzer support
 
 go-fuzz-build can also generate an archive file