Group entity. Group has many projects

app/models/group.rb

@@ -0,0 +1,22 @@
+# == Schema Information
+#
+# Table name: groups
+#
+#  id         :integer         not null, primary key
+#  name       :string(255)     not null
+#  code       :string(255)     not null
+#  owner_id   :integer         not null
+#  created_at :datetime        not null
+#  updated_at :datetime        not null
+#
+
+class Group < ActiveRecord::Base
+  attr_accessible :code, :name, :owner_id
+
+  has_many :projects
+  belongs_to :owner, class_name: "User"
+
+  validates :name, presence: true, uniqueness: true
+  validates :code, presence: true, uniqueness: true
+  validates :owner_id, presence: true
+end