code: function init(options) {
      validate(options);
      setAuthConfig(options.config);
      setAcl(options.acl);
      setModels(options.models);
  }
docs: Main initialization method
  @param {object} options is an object with keys for:
  config: the authConfig detailing rules for each model
  models: an object containing modelName: Model key pairs
  acl: the Action Control List object containing methods for each context
  @return {null} the shield internals are private