Specify latest redis tag.

To stop fig pulling every damn version.
Merge pull request #263 from astopy/master

Specify latest redis tag.
Return version and content_language with workflow
Reject classifications without required metadata
apt-get upgrade during docker build
Merge pull request #267 from astopy/master

apt-get upgrade during docker build
Add missing && to Dockerfile.
Merge pull request #269 from astopy/master

Add missing && to Dockerfile.
Fix Controller versioning examples
Add versioning specs to versioned controllers
Rename sort random to sort cellect

closes #257
Merge pull request #272 from edpaget/rename-random-to-cellect

Rename sort random to sort cellect
Merge pull request #265 from edpaget/add-workflow-version-to-classification

Add workflow version to classification
Merge pull request #270 from edpaget/add-versioning-spec-to-controllers

Add versioning spec to controllers
add gold_standard attribute to classification

track if the classification was made by a user with an 'expert' role on the project
add project expert classifier method

use project roles scope to determine who an expert classifier is
record gold standard data in classification lifecycle
ensure add gold standard runs in transact!
spec out non-logged in user gold standard behaviour
move to enum field for expert classifier level