This builds a thrift image using our fork. It's used in the thrift
files repo to generate the committed code.
The docker image is built using [automated builds][] on Docker hub.
Simply push to the master branch to build saltside/thrift:latest or
push a tag (e.g 0.9.2) to build saltide/thrift:0.9.2.
Automation is linked with the automation user (github & docker hub in this case).