code: function _createManifest(){
          let file = repositoryPath + '/manifest.json';
          let manifest = {
              machines: {}
          };
  
          return new Promise(function(resolve, reject) {
              debug("Creating manifest file");
              jsonfile.writeFile(file, manifest, function (err) {
                  if(err){
                      debug("Failed to create the manifest file");
                      reject(err);
                      return;
                  }
                  resolve();
              });
          });
      }
docs: Create the manifest file inside the repository
  @method _createManifest
  @returns {Promise}