Added Rubocop and initial config

Gemfile

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source "https://rubygems.org"
 
 # Bundle edge Rails instead: gem "rails", github: "rails/rails", branch: "main"
@@ -21,7 +23,7 @@ gem "jbuilder"
 gem "bcrypt", "~> 3.1.7"
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
-gem "tzinfo-data", platforms: %i[ windows jruby ]
+gem "tzinfo-data", platforms: %i[windows jruby]
 
 # Use the database-backed adapters for Rails.cache, Active Job, and Action Cable
 gem "solid_cache"
@@ -41,7 +43,7 @@ gem 'slim'
 
 group :development, :test do
   # See https://guides.rubyonrails.org/debugging_rails_applications.html#debugging-with-the-debug-gem
-  gem "debug", platforms: %i[ mri windows ], require: "debug/prelude"
+  gem "debug", platforms: %i[mri windows], require: "debug/prelude"
 
   # Static analysis for security vulnerabilities [https://brakemanscanner.org/]
   gem "brakeman", require: false
@@ -50,4 +52,7 @@ end
 group :development do
   # Use console on exceptions pages [https://github.com/rails/web-console]
   gem "web-console"
+
+  gem 'rubocop', require: false
+  gem 'rubocop-rails', require: false
 end