Add optional template for mktemp, so that it works in Mac too.

GNU mktemp does not require a template as a required argument while the
FreeBSD version that comes with the Mac, needs it:

GNU mktemp:
   mktemp [option]... [template]

FreeBSD mktemp
   mktemp [-d] [-q] [-u] template

I have just added a template in the form XXXXXXXX so that it works in
both environments.
Add prefix to generate tmp files in /tmp, except for the exercise repos
Change template from GITPractice_XXXXXXXX to GITPractice_Repo_XXXXXXXX
Change the template for the remote repos to GITPractice_REMOTE_REPO_XXXXXXXX
Correct commit message.
Initial commit
fixed the spelling errors
Correct commit message.
Initial commit