code: function runSQL (sql, config, conn, replacements) {
    return new Promise(function (resolve, reject) {
      if (!config && !conn) {
        reject('Must set config or connection')
      }
  
      if (!sql) {
        reject('Need some sql')
      }
  
      if (!conn) {
        conn = getConnection(config)
      }
  
      replacements = replacements || {}
  
      conn.query(sql, { replacements: replacements }).then(function (ret) {
        return resolve({'ret': ret, 'conn': conn})
      }).catch(function (err) {
        return reject(err)
      })
    })
  }
docs: Run SQL as promise
  @param  {string} sql          The SQL to run
  @param  {Object} config          The config object.
  @param  {string} config.dialect  The db dialect sqlite | mysql.
  @param  {string} config.host     The db host.
  @param  {string} config.database The db database name.
  @param  {string} config.username The db username.
  @param  {string} config.password The db password.
  @param  {Object} conn            Sequelize connection.
  @param  {Object} replacements    Possiblle replacements.
  @return {Object}                 Promise