Added Rubocop and initial config

app/models/project.rb

@@ -1,23 +1,18 @@
+# frozen_string_literal: true
+
 class Project < ApplicationRecord
   validates :name, :code, presence: true
   validates :code, exclusion: { in: %w[new] }, uniqueness: true
 
-  has_many :tasks
+  has_many :tasks, dependent: :restrict_with_exception
 
   has_rich_text :description
 
-  before_validation :lowercase_code
+  normalizes :code, with: ->(code) { code.strip.downcase }
 
   def to_param
     return unless id
+
     code
   end
-
-  private
-
-  def lowercase_code
-    return if code.blank?
-
-    self.code = self.code.downcase
-  end
 end