Fix handling of 'cmd'
nargs='*' made a lot of other parsing fail with strange
errors.
MODIFY
repo2docker/app.py
repo2docker/app.py
@@ -152,7 +152,7 @@ class Repo2Docker(Application):
argparser.add_argument(
'cmd',
- nargs='*',
+ action='append',
help='Custom command to run after building container'
)

Fix handling of 'cmd'

nargs='*' made a lot of other parsing fail with strange
errors.