Writing CV's for a "summer school" course
Of course I don't know anything about this particular course, but often, admission to summer school courses is not at all competitive, and there are seats (and sometimes funding) for more or less every serious student who shows interest.  (If it were competitive, I'd expect them to at least want a letter of recommendation.)

So basically your CV has to convince them of the following:


You are an actual grad student, and not some goofball trying to use them to get a visa.  So be sure to include your academic history (degrees and dates, honors if any) and the details of the program in which you are currently enrolled.  Definitely give your supervisor's name.
The course will be interesting and relevant to you.  Mention your areas of scientific interest (they should be at least tangentially related to the topic of the course).  List any relevant research projects, past or present, even if they are fairly minor.  Definitely include any published papers or conference presentations.
You have sufficient background to learn something from the course, and not get completely lost (getting a little bit lost is normal).  Briefly mention your GPAs and scholarships.  If it seems appropriate, list classes you have taken or books you have read that would prepare you for this course.