Pass UID and GID to docker run task as env variables

docker.py

 from __future__ import unicode_literals
 
+import os
+
 from fabric.api import task, roles, env, local, run, lcd, execute
 from fabric.colors import red, green
 from fabric.contrib.console import confirm
@@ -54,6 +56,9 @@ def docker_tryrun(imgname, containername=None, opts='', mounts=None, cmd='', res
     else:
         containername_opt = ''
 
+    opts += ' -e USER_ID={}'.format(os.getuid())
+    opts += ' -e GROUP_ID={}'.format(os.getgid())
+
     local('docker run %s %s %s %s' % (opts, containername_opt, imgname, cmd))
     return True