Update User#identifier to conform to Gitolite 2.x's user pattern

Also modifies the specs a bit because I can't help myself.

Closes #480

app/roles/account.rb

 module Account
+  # Returns a string for use as a Gitolite user identifier
+  #
+  # Note that Gitolite 2.x requires the following pattern for users:
+  #
+  #   ^@?[0-9a-zA-Z][0-9a-zA-Z._\@+-]*$
   def identifier
-    email.gsub /[^[:alnum:]]/, "_"
+    # Replace non-word chars with underscores, then make sure it starts with
+    # valid chars
+    email.gsub(/\W/, '_').gsub(/\A([\W\_])+/, '')
   end
 
   def is_admin?

spec/factories.rb

@@ -28,7 +28,7 @@ FactoryGirl.define do
     email { Faker::Internet.email }
     name
     password "123456"
-    password_confirmation "123456"
+    password_confirmation { password }
 
     trait :admin do
       admin true

spec/models/user_spec.rb

@@ -31,36 +31,46 @@ describe User do
     it { should respond_to(:private_token) }
   end
 
+  describe '#identifier' do
     it "should return valid identifier" do
-    user = User.new(email: "test@mail.com")
+      user = build(:user, email: "test@mail.com")
       user.identifier.should == "test_mail_com"
     end
 
     it "should return identifier without + sign" do
-    user = User.new(email: "test+foo@mail.com")
+      user = build(:user, email: "test+foo@mail.com")
       user.identifier.should == "test_foo_mail_com"
     end
 
+    it "should conform to Gitolite's required identifier pattern" do
+      user = build(:user, email: "_test@example.com")
+      user.identifier.should == 'test_example_com'
+    end
+  end
+
+  describe '#generate_password' do
     it "should execute callback when force_random_password specified" do
-    user = User.new(email: "test@mail.com", force_random_password: true)
+      user = build(:user, force_random_password: true)
       user.should_receive(:generate_password)
       user.save
     end
 
     it "should not generate password by default" do
-    user = Factory(:user, password: 'abcdefg', password_confirmation: 'abcdefg')
+      user = create(:user, password: 'abcdefg')
       user.password.should == 'abcdefg'
     end
 
     it "should generate password when forcing random password" do
       Devise.stub(:friendly_token).and_return('123456789')
-    user = User.create(email: "test1@mail.com", force_random_password: true)
-    user.password.should == user.password_confirmation
+      user = create(:user, password: 'abcdefg', force_random_password: true)
       user.password.should == '12345678'
     end
+  end
 
+  describe 'authentication token' do
     it "should have authentication token" do
       user = Factory(:user)
-    user.authentication_token.should_not == ""
+      user.authentication_token.should_not be_blank
+    end
   end
 end