Comment 0 for bug 1233697

Two new DB tables:

artifact_group:
  - id
  - name
  - group_type ("map", "calculation", etc.)
  - user_id (FK to Django User table)

artifact_group_link:
  - id
  - artifact_id (FK to icebox's Artifact table)
  - artifact_group_id (FK to icebox's ArtifactGroup table)

Two new REST API methods:

- GET /icebox/artifact_groups
- GET /icebox/artifact_group/:group_id