Project create

app/models/project.rb

@@ -1,12 +1,23 @@
 class Project < ApplicationRecord
   validates :name, :code, presence: true
+  validates :code, exclusion: { in: %w[new] }, uniqueness: true
 
   has_many :tasks
 
   has_rich_text :description
 
+  before_validation :lowercase_code
+
   def to_param
     return unless id
     code
   end
+
+  private
+
+  def lowercase_code
+    return if code.blank?
+
+    self.code = self.code.downcase
+  end
 end