gistfile1.txt

[root@pike-aio ~(keystone_admin)]# keystone-manage mapping_engine --rules rules.json --input rules.test
{
  "group_ids": [],
  "user": {
    "domain": {
      "name": "Default"
    },
    "type": "local",
    "name": "bob"
  },
  "projects": [],
  "group_names": []
}

rules.json

[
  {
    "remote": [
      {
        "type": "MELLON_ks_username"
      },
      {
        "type": "MELLON_groups"
      }
    ],
    "local": [
      {
        "user": {
          "name": "{0}",
          "type": "local",
          "domain": {
            "name": "Default"
          }
        }
      }
    ]
  }
]

rules.test

MELLON_email: me@you.com
MELLON_groups:
MELLON_ks_username: bob