set bcrypt rounds to 10

config/initializers/devise.rb

@@ -120,7 +120,7 @@ Devise.setup do |config|
   # a value less than 10 in other environments. Note that, for bcrypt (the default
   # algorithm), the cost increases exponentially with the number of stretches (e.g.
   # a value of 20 is already extremely slow: approx. 60 seconds for 1 calculation).
-  config.stretches = Rails.env.test? ? 1 : 12
+  config.stretches = Rails.env.test? ? 1 : 10
 
   # Set up a pepper to generate the hashed password.
   # Send a notification to the original email when the user's email is changed.