diff --git a/app/models/environment.rb b/app/models/environment.rb
index d3a13a6..65c31f7 100644
--- a/app/models/environment.rb
+++ b/app/models/environment.rb
@@ -220,6 +220,19 @@ class Environment < ActiveRecord::Base
     end
   end
 
+  # Whether this environment should force having 'www.' in its domain name or
+  # not. Defauls to false.
+  #
+  # See also #default_hostname
+  def force_www
+    settings[:force_www] || false
+  end
+
+  # Sets the value of #force_www. <tt>value</tt> must be a boolean.
+  def force_www=(value)
+    settings[:force_www] = value
+  end
+
   # #################################################
   # Validations
   # #################################################
@@ -248,11 +261,16 @@ class Environment < ActiveRecord::Base
     Category.top_level_for(self)
   end
 
+  # Returns the hostname of the first domain associated to this environment.
+  #
+  # If #force_www is true, adds 'www.' at the beginning of the hostname. If the
+  # environment has not associated domains, returns 'localhost'.
   def default_hostname
     if self.domains(true).empty?
       'localhost'
     else
-      self.domains.find(:first, :order => 'id').name
+      domain = self.domains.find(:first, :order => 'id').name
+      force_www ? ('www.' + domain) : domain
     end
   end
 
diff --git a/test/unit/environment_test.rb b/test/unit/environment_test.rb
index 8753a74..8e0cb88 100644
--- a/test/unit/environment_test.rb
+++ b/test/unit/environment_test.rb
@@ -172,6 +172,12 @@ class EnvironmentTest < Test::Unit::TestCase
     assert_equal 'localhost', env.default_hostname
   end
 
+  should 'add www when told to force www' do
+    env = Environment.create!(:name => 'test environment', :force_www => true)
+    env.domains << Domain.create(:name => 'example.com')
+    assert_equal 'www.example.com', env.default_hostname
+  end
+
   should 'provide default top URL' do
     env = Environment.new
     env.expects(:default_hostname).returns('www.lalala.net')
--
libgit2 0.21.2