I use IntelliJ IDEA as golang IDE in Windows , and system environment have already set GOPATH，but IDEA can't load $GOPATH. 

go get github.com/astaxie/beego

I have added this package in project's structure in this way:

enter image description here

and this project's choice “Go sdk go1.1.1 windows/amd64 ”like enter image description here

how can I set GOPATH in idea?