code: function Adapter(params) {
  	this.params = params || {};
  
  	if (!this.params.dir) {
  		throw new Error('`dir` parameter required');
  	}
  
  	this.migrationsFilePath = (
  		this.params.migrationsFile ||
  		pathUtils.join(this.params.dir, '.migrations')
  	);
  
  	this.dir = __dirname;
  }
docs: Fs adapter stores executed migration in file system.
  NOTICE: because of entry file is read and write and it's async operations
  parallel execution of write operations (`markExecuted` or `unmarkExecuted`)
  could break executed migrations list.