diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 0000000..276cbf9
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+2.3.0
diff --git a/rswag-specs/lib/rswag/specs/extended_schema.rb b/rswag-specs/lib/rswag/specs/extended_schema.rb
index 379868d..18bd940 100644
--- a/rswag-specs/lib/rswag/specs/extended_schema.rb
+++ b/rswag-specs/lib/rswag/specs/extended_schema.rb
@@ -2,11 +2,10 @@ require 'json-schema'
 
 module Rswag
   module Specs
-    class ExtendedSchema < JSON::Schema::Validator
+    class ExtendedSchema < JSON::Schema::Draft4
 
       def initialize
         super
-        extend_schema_definition("http://json-schema.org/draft-04/schema#")
         @attributes['type'] = ExtendedTypeAttribute
         @uri = URI.parse('http://tempuri.org/rswag/specs/extended_schema')
       end
diff --git a/test-app/app/models/blog.rb b/test-app/app/models/blog.rb
index 51b0795..e913dba 100644
--- a/test-app/app/models/blog.rb
+++ b/test-app/app/models/blog.rb
@@ -5,7 +5,7 @@ class Blog < ActiveRecord::Base
     {
       id: id,
       title: title,
-      content: content
+      content: nil
     }
   end
 end
diff --git a/test-app/config/environments/development.rb b/test-app/config/environments/development.rb
index 7886e90..9bcfc66 100644
--- a/test-app/config/environments/development.rb
+++ b/test-app/config/environments/development.rb
@@ -28,4 +28,6 @@ TestApp::Application.configure do
 
   # Expands the lines which load the assets
   config.assets.debug = true
+
+  config.eager_load = false
 end
diff --git a/test-app/config/environments/production.rb b/test-app/config/environments/production.rb
deleted file mode 100644
index a9a5401..0000000
--- a/test-app/config/environments/production.rb
+++ /dev/null
@@ -1,67 +0,0 @@
-TestApp::Application.configure do
-  # Settings specified here will take precedence over those in config/application.rb
-
-  # Code is not reloaded between requests
-  config.cache_classes = true
-
-  # Full error reports are disabled and caching is turned on
-  config.consider_all_requests_local       = false
-  config.action_controller.perform_caching = true
-
-  # Disable Rails's static asset server (Apache or nginx will already do this)
-  config.serve_static_assets = true
-
-  # Compress JavaScripts and CSS
-  config.assets.compress = true
-
-  # Don't fallback to assets pipeline if a precompiled asset is missed
-  config.assets.compile = false
-
-  # Generate digests for assets URLs
-  config.assets.digest = true
-
-  # Defaults to nil and saved in location specified by config.assets.prefix
-  # config.assets.manifest = YOUR_PATH
-
-  # Specifies the header that your server uses for sending files
-  # config.action_dispatch.x_sendfile_header = "X-Sendfile" # for apache
-  # config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for nginx
-
-  # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
-  # config.force_ssl = true
-
-  # See everything in the log (default is :info)
-  # config.log_level = :debug
-
-  # Prepend all log lines with the following tags
-  # config.log_tags = [ :subdomain, :uuid ]
-
-  # Use a different logger for distributed setups
-  # config.logger = ActiveSupport::TaggedLogging.new(SyslogLogger.new)
-
-  # Use a different cache store in production
-  # config.cache_store = :mem_cache_store
-
-  # Enable serving of images, stylesheets, and JavaScripts from an asset server
-  # config.action_controller.asset_host = "http://assets.example.com"
-
-  # Precompile additional assets (application.js, application.css, and all non-JS/CSS are already added)
-  # config.assets.precompile += %w( search.js )
-
-  # Disable delivery errors, bad email addresses will be ignored
-  # config.action_mailer.raise_delivery_errors = false
-
-  # Enable threaded mode
-  # config.threadsafe!
-
-  # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
-  # the I18n.default_locale when a translation can not be found)
-  config.i18n.fallbacks = true
-
-  # Send deprecation notices to registered listeners
-  config.active_support.deprecation = :notify
-
-  # Log the query plan for queries taking more than this (works
-  # with SQLite, MySQL, and PostgreSQL)
-  # config.active_record.auto_explain_threshold_in_seconds = 0.5
-end
diff --git a/test-app/config/environments/test.rb b/test-app/config/environments/test.rb
index 6dd0bf7..3a35ac5 100644
--- a/test-app/config/environments/test.rb
+++ b/test-app/config/environments/test.rb
@@ -32,4 +32,6 @@ TestApp::Application.configure do
 
   # Print deprecation notices to the stderr
   config.active_support.deprecation = :stderr
+
+  config.eager_load = false
 end
diff --git a/test-app/config/initializers/secret_token.rb b/test-app/config/initializers/secret_token.rb
index 706e45d..843ff63 100644
--- a/test-app/config/initializers/secret_token.rb
+++ b/test-app/config/initializers/secret_token.rb
@@ -5,3 +5,6 @@
 # Make sure the secret is at least 30 characters and all random,
 # no regular words or you'll be exposed to dictionary attacks.
 TestApp::Application.config.secret_token = '60f36cd33756d73f362053f1d45256ae50d75440b634ae73b070a6e35a2df38692f59e28e5ecbd1f9f2e850255f6d29a468bc59ac4484c2b7f0548ddbfc1b870'
+
+# See http://guides.rubyonrails.org/upgrading_ruby_on_rails.html#config-secrets-yml
+TestApp::Application.config.secret_key_base = 'f6a820cc8aa76094583cd68ef46a735e25e3278648086355f8bd24721f036959c728c06a28dcecfe695f17ae2db44dfa1424f22b81377f2a1496d4e19f6f7faa'
diff --git a/test-app/db/schema.rb b/test-app/db/schema.rb
index 4e72efd..cea4d93 100644
--- a/test-app/db/schema.rb
+++ b/test-app/db/schema.rb
@@ -13,10 +13,10 @@
 ActiveRecord::Schema.define(version: 20160218212104) do
 
   create_table "blogs", force: :cascade do |t|
-    t.string "title"
+    t.string "title", limit: 255
     t.text "content"
-    t.datetime "created_at"
-    t.datetime "updated_at"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
   end
 
 end
diff --git a/test-app/spec/swagger_helper.rb b/test-app/spec/swagger_helper.rb
index a3b76b4..f3202ec 100644
--- a/test-app/spec/swagger_helper.rb
+++ b/test-app/spec/swagger_helper.rb
@@ -39,7 +39,7 @@ RSpec.configure do |config|
           properties: {
             id: { type: 'integer' },
             title: { type: 'string' },
-            content: { type: 'string' }
+            content: { type: 'string', 'x-nullable': true }
           },
           required: [ 'id', 'title', 'content' ]
         }
diff --git a/test-app/swagger/v1/swagger.json b/test-app/swagger/v1/swagger.json
index acbcd1e..7ee0753 100644
--- a/test-app/swagger/v1/swagger.json
+++ b/test-app/swagger/v1/swagger.json
@@ -146,7 +146,8 @@
           "type": "string"
         },
         "content": {
-          "type": "string"
+          "type": "string",
+          "x-nullable": true
         }
       },
       "required": [