add ioredis instrumentation plugin

[vmarchaud]

cc @mayurkale22 @draffensperger

[codecov-io]

Codecov Report

Merging #410 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #410      +/-   ##
=========================================
- Coverage   94.81%   94.8%   -0.01%     
=========================================
  Files         136     138       +2     
  Lines        9000    9086      +86     
  Branches      666     667       +1     
=========================================
+ Hits         8533    8614      +81     
- Misses        467     472       +5

Impacted Files	Coverage Δ
src/prometheus-stats.ts	92.78% <0%> (-1.1%)	⬇️
src/stats/view.ts	97.43% <0%> (-0.24%)	⬇️
test/test-view.ts	98.17% <0%> (-0.21%)	⬇️
src/stats/recorder.ts	97.56% <0%> (-0.06%)	⬇️
src/stackdriver-cloudtrace-utils.ts	97.26% <0%> (-0.04%)	⬇️
src/stats/types.ts	100% <0%> (ø)	⬆️
src/http.ts	91.21% <0%> (ø)	⬆️
test/test-recorder.ts	100% <0%> (ø)	⬆️
test/test-prometheus-stats.ts	100% <0%> (ø)	⬆️
src/mongodb.ts	91.78% <0%> (ø)	⬆️
... and 10 more

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[draffensperger]

Thanks for the contribution and for use of strong types where possible!

[vmarchaud]

I believe i've addressed every issue

[mayurkale22]

Please include Redis and IORedis in supported list of plugins -> https://github.com/census-instrumentation/opencensus-node#plugins

[mayurkale22]

Optional : s/ioredis/IORedis?

[vmarchaud]

@mayurkale22 Are you sure to add them in the global readme even though they are not currently enabled with the latest version ? We would need a separate PR to add them into instrumentation-all package so i believe this change should be done in the separate PR

[mayurkale22]

@mayurkale22 Are you sure to add them in the global readme even though they are not currently enabled with the latest version ? We would need a separate PR to add them into instrumentation-all package so i believe this change should be done in the separate PR

Makes sense 👍

[mayurkale22]

Thanks for the contribution again!