Fixed #269 Add health-check endpoint (GRN-3) (#290)

* <Added health_check endpoint>

* <changed gemfile_lock>

* <fixed code style>

* <removed excess health_check routes>

config/routes.rb

@@ -17,6 +17,8 @@
 # with BigBlueButton; if not, see <http://www.gnu.org/licenses/>.
 
 Rails.application.routes.draw do
+  get 'health_check', to: 'health_check/health_check#index'
+
   # Error routes.
   match '/404', to: 'errors#not_found', via: :all
   match '/422', to: 'errors#unprocessable', via: :all