Only generate cost centers if running in server.

* initializers are always run after version 4 of rails. In this instance the initializer was being run by rake during the docker build process. However, the necessary env vars are not present at build time so this step was failing. Line 36 stops this.

config/initializers/cost_centers.rb

@@ -13,9 +13,18 @@ def load_from_s3(bucket, key)
   return data
 end
 
+def load_dummy_cost_centres()
+  File.read(File.join(Rails.root, 'config', 'cost_centre_fixture.csv'))
+end
+
+def running_inside_a_rake_task?
+  !defined?(Rails::Server)
+end
+
 def get_cost_centre_data()
-  if Rails.env.development?
-    return File.read(File.join(Rails.root, 'config', 'cost_centre_fixture.csv'))
+  # dont load the cost centers from s3 if were not running the server or we're not in RAILS_ENV != production
+  if Rails.env.development? or running_inside_a_rake_task?
+    return load_dummy_cost_centres()
   end
 
   begin
@@ -28,4 +37,5 @@ def get_cost_centre_data()
   end
 end
 
+
 COST_CENTRES = CostCentreReader.new(get_cost_centre_data())