Downgrade AMS

Gemfile

@@ -7,7 +7,7 @@ gem "rails_12factor"
 gem "devise", github: "plataformatec/devise"
 gem "jwt"
 gem "mutations"
-gem "active_model_serializers"
+gem "active_model_serializers", "~> 0.8.3"
 gem "ice_cube"
 gem "rack-cors", require: "rack/cors"
 gem "mysql"

Gemfile.lock

@@ -41,10 +41,8 @@ GEM
       erubis (~> 2.7.0)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    active_model_serializers (0.10.3)
-      actionpack (>= 4.1, < 6)
-      activemodel (>= 4.1, < 6)
-      jsonapi (= 0.1.1.beta2)
+    active_model_serializers (0.8.3)
+      activemodel (>= 3.0)
     activejob (5.0.0.1)
       activesupport (= 5.0.0.1)
       globalid (>= 0.3.6)
@@ -83,8 +81,6 @@ GEM
     i18n (0.7.0)
     ice_cube (0.14.0)
     json (1.8.3)
-    jsonapi (0.1.1.beta2)
-      json (~> 1.8)
     jwt (1.5.6)
     loofah (2.0.3)
       nokogiri (>= 1.5.9)
@@ -202,7 +198,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  active_model_serializers
+  active_model_serializers (~> 0.8.3)
   database_cleaner
   devise!
   factory_girl_rails

app/serializers/schedule_serializer.rb

@@ -14,16 +14,16 @@ class ScheduleSerializer < ActiveModel::Serializer
   private
 
   def start
-    if config[:start]
-      Time.parse(config[:start])
+    if options[:start]
+      Time.parse(options[:start])
     else
       Time.current.midnight - 1.day
     end
   end
 
   def finish
-    if config[:finish]
-      Time.parse(config[:finish])
+    if options[:finish]
+      Time.parse(options[:finish])
     else
       start + 1.day
     end