Removed some deprecation warnings

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