{
  "title": "GD M:N project testing",
  "datasets": [
    {
      "type": "dataset",
      "name": "visibility",
      "columns": [
        {
          "type": "anchor",
          "name": "visibility_id"
        },
        {
          "type": "reference",
          "name": "perm_user_id",
          "dataset": "permission_users"
        },
        {
          "type": "reference",
          "name": "commit_id",
          "dataset": "commits"
        }
      ]
    },
    {
      "type": "dataset",
      "name": "users",
      "columns": [
        {
          "type": "anchor",
          "name": "user_id"
        },
        {
          "type": "label",
          "name": "email",
          "reference": "user_id",
          "default_label" : true
        }
      ]
    },
    {
      "type": "dataset",
      "name": "permission_users",
      "columns": [
        {
          "type": "anchor",
          "name": "perm_user_id"
        },
        {
          "type": "label",
          "name": "email",
          "reference": "perm_user_id",
          "default_label" : true
        }
      ]
    },
    {
      "type": "dataset",
      "name": "commits",
      "columns": [
        {
          "type": "anchor",
          "name": "commit_id" 
        },
        {
          "type": "fact",
          "name": "lines_changed"
        },
        {
          "type": "reference",
          "name": "user_id",
          "dataset": "users"
        }
      ]
    }
  ]
}