golang vim-go setup

1. start with a fresh ~/.vim directory
2. install vim-plug if don't have it:

curl -fLo ~/.vim/autoload/plug.vim --create-dirs \
    https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim

3. add the following to your .vimrc file
call plug#begin()
Plug 'tpope/vim-sensible'
Plug 'fatih/vim-go'
Plug 'tmhedberg/matchit'
call plug#end()
au FileType go nmap <C-K> <Plug>(go-doc)
let g:go_fmt_command = "goimports"4. inside vim, run "PlugInstall". This installs the plugins specified above. Restart vim. All plugins should be working now.
5. For vim-go, run ":GoInstallBinaries" to install missing tools needed by vim-go
6. Now Shift-K/Ctrl-K should run go-doc for the keyword under cursor.

 Note for go-doc to work correctly, the go source code file has to be in $GOPATH/src/package-name. It cannot not be a symlink outside of GOPATH. It cannot be a raw *.go file under $GOPATH/src either. It needs to be under a package directory.