Add in the README.txt to export GOBIN env

[thefishermanhacker]

http://stackoverflow.com/questions/18149601/go-install-always-fails-no-install-directory-outside-gopath
mkdir bin
export GOBIN=$GOPATH/bin

[OJ]

Hi,

The README.txt currently states this:

Since this tool is written in Go you need install the Go language/compiler/etc. Full details of installation and set up can be found on the Go language website.

This text includes links on how to set up a working build environment. Reproduction of this information is not only unnecessary, but it opens the door for future inaccuracies when things change and don't get updated here.

Sorry, but my stance here is that setting up a Go build environment is the responsibility of the user, and I won't be documenting any information on that here until such times as the gobuster build process becomes non-standard.

Thanks!