Adds ENV vars for configuring the BB server

[microstudi]

fixes #287
supersedes #301

[andreslucena]

Two small changes, let me know if you prefer that I handle the rubocop update

[codecov-commenter]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (6e0a171) 69.57% compared to head (a6818dc) 69.57%.

Files	Patch %	Lines
...letin_board/server/app/graphql/types/query_type.rb	66.66%	3 Missing ⚠️
...r/app/commands/sandbox/generate_load_test_stats.rb	0.00%	1 Missing ⚠️
...oard/server/app/jobs/sandbox/generate_votes_job.rb	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #310   +/-   ##
========================================
  Coverage    69.57%   69.57%           
========================================
  Files           96       96           
  Lines         1630     1630           
========================================
  Hits          1134     1134           
  Misses         496      496           

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[andreslucena]

@microstudi there's a failing spec, can you check it out please?

[microstudi]

All done @andreslucena !

[andreslucena]

As we've talked offline, you'll fix the empty line in the next PR, so I'll merge this one