diff --git a/app/models/user.rb b/app/models/user.rb
index 6c40003..557453d 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -12,4 +12,12 @@
 
 class User < ActiveRecord::Base
   attr_accessible :name, :email
+  
+  email_regex = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
+  
+  validates :name,  :presence => true,
+                    :length   => { :maximum => 50 }
+  validates :email, :presence   => true,
+                    :format     => { :with => email_regex },
+                    :uniqueness => { :case_sensitive => false }
 end
diff --git a/db/migrate/20100822012431_add_email_uniqueness_index.rb b/db/migrate/20100822012431_add_email_uniqueness_index.rb
new file mode 100644
index 0000000..95c5122
--- /dev/null
+++ b/db/migrate/20100822012431_add_email_uniqueness_index.rb
@@ -0,0 +1,9 @@
+class AddEmailUniquenessIndex < ActiveRecord::Migration
+  def self.up
+    add_index :users, :email, :unique => true
+  end
+
+  def self.down
+    remove_index :users, :email
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index aef486a..400d256 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20100821203213) do
+ActiveRecord::Schema.define(:version => 20100822012431) do
 
   create_table "users", :force => true do |t|
     t.string   "name"
@@ -19,4 +19,6 @@
     t.datetime "updated_at"
   end
 
+  add_index "users", ["email"], :name => "index_users_on_email", :unique => true
+
 end
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 44032b4..b08980c 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -1,5 +1,57 @@
 require 'spec_helper'
 
 describe User do
-  pending "add some examples to (or delete) #{__FILE__}"
+  
+  before(:each) do
+    @attr = { :name => "Example User", :email => "user@example.com" }
+  end
+  
+  it "should create a new instance given a valid attribute" do
+    User.create!(@attr)
+  end
+  
+  it "should require a name" do
+    no_name_user = User.new(@attr.merge(:name => ""))
+    no_name_user.should_not be_valid
+  end
+  
+  it "should require an email address" do
+    no_email_user = User.new(@attr.merge(:email => ""))
+    no_email_user.should_not be_valid
+  end
+  
+  it "should reject names that are too long" do
+    long_name = "a" * 51
+    long_name_user = User.new(@attr.merge(:name => long_name))
+    long_name_user.should_not be_valid
+  end
+  
+  it "should accept valid email addresses" do
+    addresses = %w[user@foo.com THE_USER@foo.bar.org first.last@foo.jp]
+    addresses.each do |address|
+      valid_email_user = User.new(@attr.merge(:email => address))
+      valid_email_user.should be_valid
+    end
+  end
+  
+  it "should reject invalid email addresses" do
+    addresses = %w[user@foo,com user_at_foo.org example.user@foo.]
+    addresses.each do |address|
+      invalid_email_user = User.new(@attr.merge(:email => address))
+      invalid_email_user.should_not be_valid
+    end
+  end
+  
+  it "should reject duplicate email addresses" do
+    User.create!(@attr)
+    user_with_duplicate_email = User.new(@attr)
+    user_with_duplicate_email.should_not be_valid
+  end
+  
+  it "should reject email addresses identical up to case" do
+    upcased_email = @attr[:email].upcase
+    User.create!(@attr.merge(:email => upcased_email))
+    user_with_duplicate_email = User.new(@attr)
+    user_with_duplicate_email.should_not be_valid
+  end
 end