title: Golang 1.6 Cannot find packages in vendor folder
body: <p>I'm on go version 1.6.2 and am trying to <code>go build</code> an application.
  Several dependencies are located inside the <code>vendor</code> folder (e.g <code>vendor/docker/libcompose/</code>) but I get a <code>cannot find package</code> when trying to load them.</p>
  
  <p>Here's an error message:</p>
  
  <pre><code>main.go:10:2: cannot find package "github.com/docker/libcompose/cli/command" in any of:
      /usr/local/opt/go/libexec/src/github.com/docker/libcompose/cli/command (from $GOROOT)
      /Users/ali/golang/src/github.com/docker/libcompose/cli/command (from $GOPATH)
  </code></pre>
  
  <p>What am I doing do wrong?</p>
  
  <p>The doc says that packages put in the <code>vendor</code> folder are loaded automatically.</p>