[WEBDEV-624] Create HealthCheckController

- Replaces static health-check which enables us to have access logging
- Update config/routes.rb

app/controllers/health_check_controller.rb

@@ -0,0 +1,5 @@
+class HealthCheckController < ApplicationController
+  def index
+    render plain: 'OK'
+  end
+end

config/routes.rb

@@ -1,3 +1,7 @@
 Rails.application.routes.draw do
   # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
+
+  ### Health check ###
+  # /health-check
+  get '/health-check', to: 'health_check#index'
 end

spec/controllers/health_check_controller_spec.rb

@@ -0,0 +1,18 @@
+# -*- coding: utf-8 -*-
+require 'rails_helper'
+
+RSpec.describe HealthCheckController do
+  describe 'GET index' do
+    before(:each) do
+      get :index
+    end
+
+    it 'should have a response with http status ok (200)' do
+      expect(response).to have_http_status(:ok)
+    end
+
+    it 'should return the text OK' do
+      expect(response.body).to eq 'OK'
+    end
+  end
+end