title: How to I specify a NuGet package comes from an external source in packages.config?
body: <p>I am working on a project that has a dependency on a NuGet project that is on an external source. We are using package restore and not committing packages into Git. For developers that do not have this source configured in their NuGet settings, is there a way to specify in the packages.config file that this package should be pulled from a different source?</p>
  
  <p>e.g.,</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;packages&gt;
    &lt;package id="Antlr" version="3.4.1.9004" targetFramework="net45" /&gt;
    &lt;package id="bootstrap" version="3.0.0" targetFramework="net45" /&gt;
    ...
  
    &lt;!-- How do I specify that this custom package comes from a different source? --&gt;
    &lt;package id="MyCustomPackage" version="1.0.0" targetFramework="net45" /&gt;
  
    ...
    &lt;package id="Respond" version="1.2.0" targetFramework="net45" /&gt;
    &lt;package id="WebGrease" version="1.5.2" targetFramework="net45" /&gt;
  &lt;/packages&gt;
  </code></pre>