title: Adding a new project to an existing solution in TFS
body: <p>I added a project to an existing solution that is currently under source control using TFS, but for some reason I cannot check in the new project.  When I view my pending changes, none of the files in the new project show up.  None of the files have a plus (for a new file) next to them.  What did I do wrong?  How do I fix it?  It's time to check in.</p>