ember 3.18 version update modifications

app/serializers/to-json.coffee

@@ -0,0 +1,8 @@
+import DS from 'ember-data'
+
+export default DS.JSONSerializer.extend
+  keyForRelationship: (key, typeClass, method) ->
+    switch typeClass
+      when 'belongsTo' then "#{key}_id"
+      else key
+  shouldSerializeHasMany: -> false