Optimize execution duration for rspec specs

* Use in memory sqlite database for test environment
* Monkey patch BCrypt default cost factor
* Clean spec/spec_helper.rb

spec/spec_helper.rb

@@ -1,27 +1,16 @@
 # This file is copied to spec/ when you run 'rails generate rspec:install'
-ENV["RAILS_ENV"] ||= 'test'
-require File.expand_path("../../config/environment", __FILE__)
+ENV['RAILS_ENV'] ||= 'test'
+require File.expand_path('../../config/environment', __FILE__)
 require 'rspec/rails'
 
 # Requires supporting ruby files with custom matchers and macros, etc,
 # in spec/support/ and its subdirectories.
-Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}
+Dir[Rails.root.join('spec/support/**/*.rb')].each {|f| require f}
 
 RSpec.configure do |config|
-  # == Mock Framework
-  #
-  # If you prefer to use mocha, flexmock or RR, uncomment the appropriate line:
-  #
-  # config.mock_with :mocha
-  # config.mock_with :flexmock
-  # config.mock_with :rr
   config.mock_with :rspec
-
-  # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
   config.fixture_path = "#{::Rails.root}/spec/fixtures"
-
-  # If you're not using ActiveRecord, or you'd prefer not to run each of your
-  # examples within a transaction, remove the following line or assign false
-  # instead of true.
   config.use_transactional_fixtures = true
 end
+
+load "#{Rails.root.to_s}/db/schema.rb"

spec/support/decrease_bcrypt_cost_factor.rb

@@ -0,0 +1,8 @@
+module BCrypt
+  class Engine
+    [:DEFAULT_COST, :MIN_COST].each do |sym|
+      remove_const  sym
+      const_set     sym, 1
+    end
+  end
+end