text: require('dotenv').config();
  const redis = require('redis');
  const async_redis = require('async-redis');
  const client = redis.createClient(process.env.REDIS_PORT, process.env.REDIS_HOST);
  const async_client = async_redis.createClient(process.env.REDIS_PORT, process.env.REDIS_HOST);
  const student_map = require('../student_map.json');
  
  async_client.on('error', (error) => {
      console.error(error);
      throw error;
  });
  
  // store student id and mail as KVP in redis cache
  // this happense at every instantiation of the app
  const set_students_db = () => {
      console.log('setting up student Database...');
      student_map.promos.forEach(year => {
          year.students.forEach(stud => {
              async_client.set(stud.id, stud.mail);
          });
      });
      console.log('setup done.');
  }
  
  set_students_db();
  
  module.exports = { client, async_client };
  