Group creation without tags does not work.

[Morgazipa]

About

When creating a new group, an error occurs if no tag is added. Should be easy to fix.

Steps to Reproduce

• Login with any user
• Go to groups page by clicking "Groups" in the dropdown on the top right of the page
• Scroll down and click "Create New Group"
• Fill out title and description, leave tags field empty
• Click "Create"
• You should see the django generated error page: "KeyError at /groups/create/".