[Feature Request]: Add ability to pass environment variables

[rowhit]

I am wondering if it is possible to pass environment variables at the time of creation.

To push it further, would it make sense to support this tool as an extension in Dockerfile.
Ex:
DOCKERIZE [/path/to/the/binary1,/path/to/the/binary2,...]

The above would allow simply build the lean docker image with existing workflow thus broader reach.