Set version for HTTParty dependency, add opts in mailer

Gemfile

@@ -59,7 +59,7 @@ gem 'delayed_paperclip',
     git: 'https://github.com/jrgifford/delayed_paperclip.git',
     ref: 'fcf574c'
 gem 'faker' # Generate fake data
-gem 'httparty'
+gem 'httparty', '~> 0.13.1'
 gem 'i18n-js', '~> 3.0' # Localization in javascript files
 gem 'jbuilder' # JSON structures via a Builder-style DSL
 gem 'logging', '~> 2.0.0'

Gemfile.lock

@@ -247,7 +247,8 @@ GEM
     hammerjs-rails (2.0.8)
     hashdiff (0.3.8)
     hashie (3.5.7)
-    httparty (0.16.2)
+    httparty (0.13.7)
+      json (~> 1.8)
       multi_xml (>= 0.5.2)
     i18n (0.9.5)
       concurrent-ruby (~> 1.0)
@@ -600,7 +601,7 @@ DEPENDENCIES
   faker
   figaro
   hammerjs-rails
-  httparty
+  httparty (~> 0.13.1)
   i18n-js (~> 3.0)
   jbuilder
   jquery-rails

app/mailers/app_mailer.rb

@@ -23,15 +23,14 @@ class AppMailer < Devise::Mailer
     mail(headers)
   end
 
-  def system_notification(user, system_notification)
+  def system_notification(user, system_notification, opts = {})
     @user = user
     @system_notification = system_notification
 
     headers = {
       to: @user.email,
-      subject: "[#{t('system_notifications.emails.title')}] "\
-               "#{@system_notification.title}"
-    }
+      subject: t('system_notifications.emails.subject')
+    }.merge(opts)
 
     mail(headers)
   end

config/locales/en.yml

@@ -1293,7 +1293,7 @@ en:
       success_flash: "Successfully added sample group <strong>%{sample_group}</strong> to team <strong>%{team}</strong>."
   system_notifications:
     emails:
-      title: "What's new notification"
+      subject: "You've received a What's new notification"
       intro_paragraph: "Hello %{user_name}, you received new What's new notification!"
     index:
       whats_new: "What's New"