Indexes in model definition file causes automigrate to crash

edu-content-metadata-edu-content-tag.json

{
  "name": "EduContentMetadataEduContentTag",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {
  },
  "validations": [],
  "relations": {
    "eduContentMetadata": {
      "type": "belongsTo",
      "model": "EduContentMetadata",
      "foreignKey": "EduContentMetadataId"
    },
    "eduContentTag": {
      "type": "belongsTo",
      "model": "EduContentTag",
      "foreignKey": "EduContentTagId"
    }
  },
  "acls": [],
  "methods": [],
  "indexes": {
    "metadata_tag": {
      "keys": {
        "EduContentMetadataId": 1,
        "EduContentTagId": -1
      },
      "options": {
        "unique": true
      }
    }
  }
}

edu-content-metadata.json

{
  "name": "EduContentMetadata",
  "base": "PersistedModel",
  "idInjection": true,
  "properties": {
    "version": {
      "type": "number",
      "required": true
    },
    "metaVersion": {
      "type": "string",
      "required": true
    },
    "fileType": {
      "type": "string"
    },
    "author": {
      "type": "string",
      "required": true
    },
    "ISBN": {
      "type": "string"
    },
    "language": {
      "type": "string",
      "required": true
    },
    "title": {
      "type": "string",
      "required": true
    },
    "description": {
      "type": "string",
      "required": true
    },
    "created": {
      "type": "date",
      "required": true
    },
    "published": {
      "type": "date",
      "required": true
    },
    "quotable": {
      "type": "boolean",
      "required": true
    }
  },
  "validations": [],
  "relations": {
    "tags": {
      "type": "hasMany",
      "model": "EduContentTag",
      "foreignKey": "eduContentMetadataId",
      "through": "EduContentMetadataEduContentTag"
    }
  },
  "acls": [],
  "methods": []
}

edu-content-tag.json

{
  "name": "EduContentTag",
  "base": "PersistedModel",
  "idInjection": true,
  "properties": {
    "name": {
      "type": "string",
      "required": true
    }
  },
  "validations": [],
  "relations": {
    "eduContentMetadata": {
      "type": "hasMany",
      "model": "EduContentMetadata",
      "foreignKey": "eduContentTagId",
      "through": "EduContentMetadataEduContentTag"
    }
  },
  "acls": [],
  "methods": []
}