Add serializers for Regimen, RegimenItem

app/serializers/regimen_item_serializer.rb

@@ -0,0 +1,4 @@
+class RegimenItemSerializer < ActiveModel::Serializer
+  # TODO
+  attributes :_id, :regimen_id, :sequence, :time_offset
+end

app/serializers/regimen_serializer.rb

@@ -0,0 +1,3 @@
+class RegimenSerializer < ActiveModel::Serializer
+  attributes :_id, :name, :color, :device_id, :regimen_items
+end