Add posibility for custom volumes

[Nierhoff]

Hi,

As mentioned in #125 here is a way to add custom volumes, which could be used for a dedicated logvolume.

deploy:
  volumeMounts:
    - name: logs
      mountPath: /logs
  volumes:
    - name: logs
      emptyDir: {}

What do you think of the implementation ?

[rigazilla]

LGTM!

[rigazilla]

merged thanks @Nierhoff !