Extract Google Analytics ID out to an environment variable

TODO- in the future, consider putting this in a credential. We're not able to change the production credentials file currently, but we should change it in the future when we're able

app/controllers/home_controller.rb

@@ -1,8 +1,16 @@
 class HomeController < ActionController::Base
+  before_action :set_google_analytics_id
+
   def index
     @districts = District.all.order(:name)
     @schools = School.all
 
     @categories = Category.sorted.map { |category| CategoryPresenter.new(category: category) }
   end
+
+  private
+
+  def set_google_analytics_id
+    @google_analytics_id = ENV['GOOGLE_ANALYTICS_ID']
+  end
 end

app/controllers/sqm_application_controller.rb

@@ -3,6 +3,7 @@ class SqmApplicationController < ActionController::Base
   layout "sqm/application"
   before_action :set_schools_and_districts
   before_action :authenticate_district
+  before_action :set_google_analytics_id
 
   private
 
@@ -34,4 +35,8 @@ class SqmApplicationController < ActionController::Base
     end
   end
 
+  def set_google_analytics_id
+    @google_analytics_id = ENV['GOOGLE_ANALYTICS_ID']
+  end
+
 end