Installed Rubocop and SimpleCov for code coverage and style check

.rubocop.yml

@@ -0,0 +1,10 @@
+AllCops:
+  Exclude:
+    - 'vendor/**/*'
+    - 'spec/fixtures/**/*'
+    - 'tmp/**/*'
+    - 'config/**/*'
+    - 'config/puma*'
+    - 'bin/*'
+    - 'app/mailers/*'
+    - 'db/**/*'

config/initializers/redis.rb

@@ -1,8 +1,10 @@
 module UrlLookupCache
   class << self
     def redis
-      REDIS_INSTANCE_LIST.each do |key, redis_instance|
-        redis_instance[:object] ||= Redis.new(:url => (redis_instance[:url] || 'redis://127.0.0.1:6379'))
+      REDIS_INSTANCE_LIST.each do |_key, redis_instance|
+        redis_instance[:object] ||= Redis.new(
+          :url => (redis_instance[:url] || 'redis://127.0.0.1:6379')
+        )
       end
       REDIS_INSTANCE_LIST
     end