chore: add rubocop

Gemfile

@@ -3,3 +3,4 @@
 source "https://rubygems.org"
 
 # gem "rails"
+gem 'rubocop', require: false

Gemfile.lock

@@ -1,12 +1,43 @@
 GEM
   remote: https://rubygems.org/
   specs:
+    ast (2.4.3)
+    json (2.13.2)
+    language_server-protocol (3.17.0.5)
+    lint_roller (1.1.0)
+    parallel (1.27.0)
+    parser (3.3.9.0)
+      ast (~> 2.4.1)
+      racc
+    prism (1.4.0)
+    racc (1.8.1)
+    rainbow (3.1.1)
+    regexp_parser (2.11.2)
+    rubocop (1.80.1)
+      json (~> 2.3)
+      language_server-protocol (~> 3.17.0.2)
+      lint_roller (~> 1.1.0)
+      parallel (~> 1.10)
+      parser (>= 3.3.0.2)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 2.9.3, < 3.0)
+      rubocop-ast (>= 1.46.0, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 2.4.0, < 4.0)
+    rubocop-ast (1.46.0)
+      parser (>= 3.3.7.2)
+      prism (~> 1.4)
+    ruby-progressbar (1.13.0)
+    unicode-display_width (3.1.5)
+      unicode-emoji (~> 4.0, >= 4.0.4)
+    unicode-emoji (4.0.4)
 
 PLATFORMS
   ruby
   x86_64-linux
 
 DEPENDENCIES
+  rubocop
 
 BUNDLED WITH
    2.7.1

tests/main_test.rb

@@ -1,8 +1,8 @@
-require "minitest/autorun"
-require_relative "../main"
+require 'minitest/autorun'
+require_relative '../main'
 
 class TestMain < Minitest::Test
   def test_main
-    assert_equal true, true 
+    assert_equal true, true
   end
 end