Images with relative volumes don't work

[eschrock]

Expected Behavior

I tried to use this image:

https://github.com/misoca/dynamodb-local-persist

Which has an odd local volume directive:

VOLUME ["./db"]

Apparently you can have volumes relative to WORKDIR. We should support this.

Actual Behavior

$ titan run -- --name hello-world -p 8000:8000 -d misoca/dynamodb-local-persist:latest
Creating repository hello-world
Creating docker volume hello-world/v0 with path ./db
Exception in thread "main" io.titandata.titan.exceptions.CommandException: Command failed: [docker, run, --label, io.titandata.titan, --mount, type=volume,src=hello-world/v0,dst=./db,volume-driver=titan, --name, hello-world, -p, 8000:8000, -d, misoca/dynamodb-local-persist@sha256:5992a12934e9408dcb39b8f89a7c9598b81ba914b17c59f91f6cc112014666a4]

Steps to Reproduce the Problem

Try to run misoca/dynamodb-local-persist:latest under titan

Version

Titan 0.3.0