fix(query-orchestrator): use bluebird to promisify redis client

[vladi-dev]

fixes #84

[paveltiunov]

Hey @vladi-dev ! Thanks for providing this PR! I believe bluebird fixes your original issue. On other hand bluebird will replace/patch native Promise implementation which entails other similar issues that you faced already. I believe it's better just not to use any promisifyAll stuff here and make async methods manually one by one as list of those used methods is known.

[vladi-dev]

@paveltiunov do you mean having something like this?

const { promisify } = require('util');
['brpop', 'del', 'exec', 'get', 'hget', 'rpop', 'set', 'zadd', 'zrange', 'zrangebyscore'].forEach(
  k => promisify(redis.RedisClient.prototype[k])
);
promisify(redis.Multi.prototype.exec);

[paveltiunov]

@vladi-dev Yep. Exactly! Probably it also makes sense to promisify instances and not prototypes to avoid side effects.

[vladi-dev]

@paveltiunov please take a look at #89

[vladi-dev]

Implemented manual promisify in #89