luarocks not found on fresh install

[philipobrien]

TASK [install iTorch] **********************************************************
fatal: [default]: FAILED! => {"changed": true, "cmd": "luarocks make", "delta": "0:00:00.001566", "end": "2016-10-13 09:43:00.663253", "failed": true, "rc": 127, "start": "2016-10-13 09:43:00.661687", "stderr": "/bin/sh: 1: luarocks: not found", "stdout": "", "stdout_lines": [], "warnings": []}

running vagrant provision subsequently works