Add puma to Gemfile to fix integration tests

Gemfile

@@ -28,6 +28,7 @@ group :test do
   gem 'generator_spec'
   gem 'capybara'
   gem 'capybara-webkit'
+  gem 'puma'
 end
 
 group :assets do

test-app/db/schema.rb

@@ -1,3 +1,4 @@
+# encoding: UTF-8
 # This file is auto-generated from the current state of the database. Instead
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.
@@ -8,16 +9,16 @@
 # from scratch. The latter is a flawed and unsustainable approach (the more migrations
 # you'll amass, the slower it'll run and the greater likelihood for issues).
 #
-# It's strongly recommended that you check this file into your version control system.
+# It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160218212104) do
+ActiveRecord::Schema.define(:version => 20160218212104) do
 
-  create_table "blogs", force: :cascade do |t|
+  create_table "blogs", :force => true do |t|
     t.string   "title"
     t.text     "content"
     t.string   "thumbnail"
-    t.datetime "created_at"
-    t.datetime "updated_at"
+    t.datetime "created_at", :null => false
+    t.datetime "updated_at", :null => false
   end
 
 end