Complete refactor of Gemfile and upgraded gems (#2553)

.rubocop.yml

Gemfile

Gemfile.lock

app/controllers/account_activations_controller.rb

app/controllers/admins_controller.rb

app/controllers/application_controller.rb

app/controllers/concerns/authenticator.rb

app/controllers/concerns/rolify.rb

app/controllers/health_check_controller.rb

app/controllers/rooms_controller.rb

app/controllers/sessions_controller.rb

app/helpers/application_helper.rb

app/helpers/users_helper.rb

app/mailers/user_mailer.rb

app/models/user.rb

config/application.rb

config/environments/production.rb

config/puma.rb

db/migrate/20190726153012_add_custom_roles.rb

lib/bbb_api.rb