code: function Migrate (grunt, adapter, config, steps) {
    this.grunt = grunt;
    this.adapter = adapter;
    this.path = path.resolve(config.path);
    this.steps = steps;
  }
docs: Initialize a new migration `Migrate` with the given `grunt, adapter, path and steps`
  
  @param {Object} grunt
  @param {Adapter} adapter
  @param {String} path
  @param {Number} steps
  @api private