code: function mergeBranch(branch) {
    var mergeCmd = 'git merge --no-ff --no-edit ' + branch;
  
    console.log('Merging release into master.')
    return exec('git checkout master && ' + mergeCmd).then(function() {
      console.log('Merging release into develop.')
      return exec('git checkout develop && ' + mergeCmd);
    });
  }
docs: Merge the specified branch back into master and develop.