View resolution for Grails is based on convention. Each controller has a directory under grails-app/views for their associated views. Unless you specify otherwise (via render) the view displayed will match the controller action name.
In your case you need to move your index.gsp
to grails-app/views/
and rename your teams.gsp
to index.gsp
under grails-app/views/team
.
Hope this helps. You may want to take a look at the documentation for further information and insight.
Also, you will need to specify what controller is used by the link to show all teams.
<li><g:link controller="team" action="index">Display all teams</g:link></li>