added uglifier and redis

Gemfile

@@ -7,7 +7,7 @@ gem 'jbuilder', '~> 2.0'
 gem 'pg', '~> 0.21'
 gem 'puma'
 gem 'rails', '5.2.1'
-gem 'redis'
+gem 'redis', '~> 3.0'
 
 gem 'autoprefixer-rails'
 gem 'bootstrap-sass', '~> 3.3'

Gemfile.lock

@@ -143,7 +143,7 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
-    redis (4.0.2)
+    redis (3.3.5)
     responders (2.4.0)
       actionpack (>= 4.2.0, < 5.3)
       railties (>= 4.2.0, < 5.3)
@@ -215,7 +215,7 @@ DEPENDENCIES
   pry-rails
   puma
   rails (= 5.2.1)
-  redis
+  redis (~> 3.0)
   sass-rails
   simple_form
   spring

config/environments/production.rb

@@ -94,4 +94,7 @@ Rails.application.configure do
 
   # Do not dump schema after migrations.
   config.active_record.dump_schema_after_migration = false
+
+  # Backwards compatibility
+  config.assets.js_compressor = Uglifier.new(harmony: true)
 end