title: How do I install requirements in Go? "cannot find package"
body: <p>I'm new to Go and I'm trying to set up a Go project with minimal documentation: <a href="https://github.com/alphagov/metadata-api">https://github.com/alphagov/metadata-api</a></p>
  
  <p>I've cloned it, but when I try <code>go build</code> I get the following warnings: </p>
  
  <pre><code>main.go:8:2: cannot find package "github.com/Sirupsen/logrus" in any of:
      /usr/local/Cellar/go/1.3.3/libexec/src/pkg/github.com/Sirupsen/logrus (from $GOROOT)
      /Users/me/go/src/github.com/Sirupsen/logrus (from $GOPATH)
  main.go:14:2: cannot find package "github.com/alphagov/metadata-api/content_api" in any of:
      /usr/local/Cellar/go/1.3.3/libexec/src/pkg/github.com/alphagov/metadata-api/content_api (from $GOROOT)
      /Users/me/go/src/github.com/alphagov/metadata-api/content_api (from $GOPATH)
  </code></pre>
  
  <p>I'm guessing this is because I haven't installed the Go equivalent of requirements? </p>
  
  <p>My <code>GOPATH</code> is set:</p>
  
  <pre><code>metadata-api$ echo $GOPATH
  /Users/me/go
  </code></pre>
  
  <p>And the Go executable is in </p>
  
  <pre><code>metadata-ape$ echo $PATH
  ....:/Users/me/go/bin
  </code></pre>
  
  <p>What do I need to do to help Go find these packages?</p>