Introduce the EventType model

This model will be used to define what types of events will happen
during a conference.

app/models/event_type.rb

@@ -0,0 +1,7 @@
+class EventType < ActiveRecord::Base
+  belongs_to :conference
+  translates :name, :description
+
+  validates :name, presence: true, uniqueness: {scope: :conference, message: :must_be_unique_for_the_conference}
+  validates :description, presence: true
+end

db/migrate/20150416232523_create_event_types.rb

@@ -0,0 +1,15 @@
+class CreateEventTypes < ActiveRecord::Migration
+  def up
+    create_table :event_types do |t|
+      t.references :conference, index: true, foreign_key: true
+
+      t.timestamps null: false
+    end
+    EventType.create_translation_table! name: :string, description: :text
+  end
+
+  def down
+    drop_table :event_types
+    EventType.drop_translation_table!
+  end
+end

spec/factories/event_types.rb

@@ -0,0 +1,7 @@
+FactoryGirl.define do
+  factory :event_type do
+    name { |n| "Track #{n}" }
+    description 'MyText'
+    conference
+  end
+end

spec/models/event_type_spec.rb

@@ -0,0 +1,34 @@
+require 'rails_helper'
+
+RSpec.describe EventType, type: :model do
+
+  describe 'description' do
+    it 'must be present' do
+      expect(build(:event_type, description: nil)).to have_error_on :description
+    end
+
+    it 'is translatable' do
+      event_type = build(:event_type)
+      expect(event_type).to have_translatable :description
+    end
+  end
+
+  describe 'name' do
+    it 'must be present' do
+      expect(build(:event_type, name: nil)).to have_error_on :name
+      expect(build(:event_type, name: '')).to have_error_on :name
+    end
+
+    it 'must be unique for a event_type' do
+      conference = create :conference
+      create :event_type, name: 'foo', conference: conference
+      expect(build(:event_type, name: 'foo', conference: conference)).to have_error_on :name
+      expect(build(:event_type, name: 'foo', conference: create(:conference))).to_not have_error_on :name
+    end
+
+    it 'is translatable' do
+      event_type = build(:event_type)
+      expect(event_type).to have_translatable :name
+    end
+  end
+end