Single string command parsing to docker

[ayushjn20]

Is your feature request related to a problem? Please describe.
It is very uncomfortable to write commands in the way as required by the docker client. The present format for a command is an array of strings where the first element is the name of the binary to be used.

- command: ["npm", "install", "-g", "redis-commander"]

Describe the solution you'd like
It would be great if we could direcrly write the commands in the following way,

- command: npm instal -g redis-commander