'ds dockerfile.js' clears dockerfile.js

[gerrywastaken]

Forget to specify the output file and dockerscript will clear our your brand new dockerfile.js. This just bit me.

[summer4096]

Interesting, specifying only one parameter outputs to that path. It could throw an error if the input and output are the same. That would go around here. You can send a pull request if you like, I'd be happy to merge it.