up: add debug gem

Gemfile.lock

@@ -42,6 +42,9 @@ GEM
       activerecord (>= 5.a)
       database_cleaner-core (~> 2.0.0)
     database_cleaner-core (2.0.1)
+    debug (1.5.0)
+      irb (>= 1.3.6)
+      reline (>= 0.2.7)
     diff-lcs (1.5.0)
     docile (1.4.0)
     erubi (1.10.0)
@@ -52,6 +55,9 @@ GEM
       railties (>= 5.0.0)
     i18n (1.10.0)
       concurrent-ruby (~> 1.0)
+    io-console (0.5.11)
+    irb (1.4.1)
+      reline (>= 0.3.0)
     loofah (2.18.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
@@ -84,6 +90,8 @@ GEM
     rainbow (3.1.1)
     rake (13.0.6)
     regexp_parser (2.4.0)
+    reline (0.3.1)
+      io-console (~> 0.5)
     rexml (3.2.5)
     rspec-core (3.11.0)
       rspec-support (~> 3.11.0)
@@ -143,6 +151,7 @@ PLATFORMS
 DEPENDENCIES
   codecov
   database_cleaner
+  debug
   factory_bot_rails
   mysql2
   rating!

rating.gemspec

@@ -19,6 +19,7 @@ Gem::Specification.new do |spec|
 
   spec.add_development_dependency 'codecov'
   spec.add_development_dependency 'database_cleaner'
+  spec.add_development_dependency 'debug'
   spec.add_development_dependency 'factory_bot_rails'
   spec.add_development_dependency 'mysql2'
   spec.add_development_dependency 'rspec-rails'