diff --git a/lib/generators/sorcery/templates/initializer.rb b/lib/generators/sorcery/templates/initializer.rb
index 36df69de..59a542ce 100644
--- a/lib/generators/sorcery/templates/initializer.rb
+++ b/lib/generators/sorcery/templates/initializer.rb
@@ -107,7 +107,7 @@
   # config.twitter.key = ""
   # config.twitter.secret = ""
   # config.twitter.callback_url = "http://0.0.0.0:3000/oauth/callback?provider=twitter"
-  # config.twitter.user_info_mapping = {:email => "screen_name"}
+  # config.twitter.user_info_mapping = {:username => "screen_name"}
   #
   # config.facebook.key = ""
   # config.facebook.secret = ""
diff --git a/lib/generators/sorcery/templates/migration/core.rb b/lib/generators/sorcery/templates/migration/core.rb
index af5f721c..6ab8e929 100644
--- a/lib/generators/sorcery/templates/migration/core.rb
+++ b/lib/generators/sorcery/templates/migration/core.rb
@@ -2,6 +2,7 @@ class SorceryCore < <%= migration_class_name %>
   def change
     create_table :<%= model_class_name.tableize %> do |t|
       t.string :email,            :null => false
+      t.string :username
       t.string :crypted_password
       t.string :salt
 
@@ -9,5 +10,7 @@ def change
     end
 
     add_index :<%= model_class_name.tableize %>, :email, unique: true
+    add_index :<%= model_class_name.tableize %>, :username, unique: true
+
   end
 end
diff --git a/lib/sorcery/model/submodules/external.rb b/lib/sorcery/model/submodules/external.rb
index 3a84c23b..842ec873 100644
--- a/lib/sorcery/model/submodules/external.rb
+++ b/lib/sorcery/model/submodules/external.rb
@@ -59,6 +59,11 @@ def create_from_provider(provider, uid, attrs)
               user.send(:"#{k}=", v)
             end
 
+            # For external services that don't offer an email like twitter.
+            unless attrs.has_key?(:email) && user.attributes.has_key?('email')
+              user.send(:'email=', "#{SecureRandom.uuid}@example.com")
+            end
+
             if block_given?
               return false unless yield user
             end
diff --git a/lib/sorcery/test_helpers/internal.rb b/lib/sorcery/test_helpers/internal.rb
index 6f603c27..6d557dcd 100644
--- a/lib/sorcery/test_helpers/internal.rb
+++ b/lib/sorcery/test_helpers/internal.rb
@@ -35,23 +35,13 @@ def create_new_user(attributes_hash = nil)
       end
 
       def create_new_external_user(provider, attributes_hash = nil)
-        user_attributes_hash = attributes_hash || { username: 'gizmo' }
+        user_attributes_hash = attributes_hash || { username: 'gizmo', email: '' }
         @user = User.new(user_attributes_hash)
         @user.sorcery_adapter.save(raise_on_failure: true)
         @user.authentications.create!(provider: provider, uid: 123)
         @user
       end
 
-      def custom_create_new_external_user(provider, authentication_class, attributes_hash = nil)
-        authentication_association = authentication_class.name.underscore.pluralize
-
-        user_attributes_hash = attributes_hash || { username: 'gizmo' }
-        @user = User.new(user_attributes_hash)
-        @user.sorcery_adapter.save(raise_on_failure: true)
-        @user.send(authentication_association).create!(provider: provider, uid: 123)
-        @user
-      end
-
       def sorcery_model_property_set(property, *values)
         User.class_eval do
           sorcery_config.send(:"#{property}=", *values)
diff --git a/spec/rails_app/db/migrate/core/20101224223620_create_users.rb b/spec/rails_app/db/migrate/core/20101224223620_create_users.rb
index a542db86..400b7ecb 100644
--- a/spec/rails_app/db/migrate/core/20101224223620_create_users.rb
+++ b/spec/rails_app/db/migrate/core/20101224223620_create_users.rb
@@ -1,13 +1,15 @@
 class CreateUsers < ActiveRecord::CompatibleLegacyMigration.migration_class
   def self.up
     create_table :users do |t|
-      t.string :username,         null: false
-      t.string :email,            default: nil
+      t.string :username
+      t.string :email,            null: false
       t.string :crypted_password
       t.string :salt
 
       t.timestamps null: false
     end
+    add_index :users, :email, unique: true
+    add_index :users, :username, unique: true
   end
 
   def self.down
diff --git a/spec/shared_examples/user_shared_examples.rb b/spec/shared_examples/user_shared_examples.rb
index c563cc95..1dae3646 100644
--- a/spec/shared_examples/user_shared_examples.rb
+++ b/spec/shared_examples/user_shared_examples.rb
@@ -560,6 +560,26 @@ def self.matches?(crypted, *tokens)
       expect(User.first.username).to eq 'Noam Ben Ari'
     end
 
+    context 'with email' do
+      it 'sets passed email' do
+        expect do
+          User.create_from_provider('facebook', '123', username: 'Noam Ben Ari', email: 'bla@bla.com') { true }
+        end.to change { User.count }.by(1)
+    
+        expect(User.first.email).to eq 'bla@bla.com'
+      end
+    end
+    
+    context 'without email' do
+      it 'sets an empty string to email' do
+        expect do
+          User.create_from_provider('facebook', '123', username: 'Noam Ben Ari') { true }
+        end.to change { User.count }.by(1)
+    
+        expect(User.first.email).not_to be_empty
+      end
+    end
+
     context 'with block' do
       it 'create user when block return true' do
         expect do