[temp] add -o flag to build instructions

README.md

@@ -36,7 +36,7 @@ recommended that `GOPATH` is set to a directory in your home directory such as
 
 ```bash
 $ git clone https://github.com/peercoin/ppcd && cd ppcd
-$ go build
+$ go build -o ppcd
 # run it using ./ppcd
 ```