code: function releaseTheme(theme, version) {
    const repoPath = `.tmp/${version}/${theme}/publish`
    return setupThemeRepo(theme, version)
      .then(() => {
        console.log(chalk.blue('Committing changes...'))
        return new Promise((resolve, reject) => {
          // commit changes
          git.add(['css', 'js', 'fonts', 'bower.json', 'package.json'], (err) =>{
            if (err) return reject(err)
            git.commit(`${version} upgrade :arrow_up:`, ['.'], (err, res) => {
              if (err) return reject(err)
              // tag current version (3.3.7-cerulean)
              git.addTag(cleanVersion(version) + '-' + theme, (err) => {
                if (err) return reject(err)
                console.log(chalk.blue('Pushing commit...'))
                // push commit
                git.push('origin', theme, (err) => {
                  if (err) return reject(err)
                  console.log(chalk.blue('Pushing tag...'))
                  // push new tag
                  git.pushTags('origin', (err) => {
                    if (err) return reject(err)
                    console.log(chalk.green(`${theme} published.`))
                    resolve()
                  })
                })
              })
            })
          })
        })
      })
  }
docs: Releases new theme version
  @param  {String} theme   Theme name
  @param  {String} version Semver
  @return {Promise}