diff --git a/app/models/profile.rb b/app/models/profile.rb
index e966a49..05edd64 100644
--- a/app/models/profile.rb
+++ b/app/models/profile.rb
@@ -100,7 +100,35 @@ class Profile < ActiveRecord::Base
 
   has_many :tasks, :foreign_key => :target_id
 
-  has_and_belongs_to_many :categories
+  has_many :profile_categorizations, :conditions => { :virtual => false }
+  has_many :categories, :through => :profile_categorizations
+
+  def pending_categorizations
+    @pending_categorizations ||= []
+  end
+
+  def add_category(c)
+    if self.id
+      ProfileCategorization.create!(:category => c, :profile => self)
+    else
+      pending_categorizations << c
+    end
+  end
+
+  def category_ids=(ids)
+    ProfileCategorization.remove_all_for(self)
+    ids.each do |item|
+      add_category(Category.find(item))
+    end
+  end
+
+  after_create :create_pending_categorizations
+  def create_pending_categorizations
+    pending_categorizations.each do |item|
+      ProfileCategorization.create!(:category => item, :profile => self)
+    end
+    pending_categorizations.clear
+  end
 
   def top_level_articles(reload = false)
     if reload
diff --git a/app/models/profile_categorization.rb b/app/models/profile_categorization.rb
index 5447e60..ba33a92 100644
--- a/app/models/profile_categorization.rb
+++ b/app/models/profile_categorization.rb
@@ -2,4 +2,20 @@ class ProfileCategorization < ActiveRecord::Base
   set_table_name :categories_profiles
   belongs_to :profile
   belongs_to :category
+
+  after_create :associate_with_entire_hierarchy
+  def associate_with_entire_hierarchy
+    return if virtual
+
+    c = category.parent
+    while !c.nil? && !self.class.find(:first, :conditions => {:profile_id => profile, :category_id => c}) 
+      self.class.create!(:profile => profile, :category => c, :virtual => true)
+      c = c.parent
+    end
+  end
+
+  def self.remove_all_for(profile)
+    self.delete_all(:profile_id => profile.id)
+  end
+
 end
diff --git a/test/unit/profile_categorization_test.rb b/test/unit/profile_categorization_test.rb
index 09c371c..a59baf2 100644
--- a/test/unit/profile_categorization_test.rb
+++ b/test/unit/profile_categorization_test.rb
@@ -12,4 +12,45 @@ class ProfileCategorizationTest < ActiveSupport::TestCase
     assert_equal [cat.id], person.category_ids 
   end
 
+  should 'create instances for the entire hierarchy' do
+    c1 = Category.create!(:name => 'c1', :environment => Environment.default)
+    c2 = c1.children.create!(:name => 'c2', :environment => Environment.default)
+
+    p = create_user('testuser').person
+
+    assert_difference ProfileCategorization, :count, 2 do
+      ProfileCategorization.create!(:category => c2, :profile => p)
+    end
+
+    assert_equal 2, ProfileCategorization.find_all_by_profile_id(p.id).size
+  end
+
+  should 'not duplicate entry for category that is parent of two others' do
+    c1 = Category.create!(:name => 'c1', :environment => Environment.default)
+    c2 = c1.children.create!(:name => 'c2', :environment => Environment.default)
+    c3 = c1.children.create!(:name => 'c3', :environment => Environment.default)
+
+    p = create_user('testuser').person
+
+    assert_difference ProfileCategorization, :count, 3 do
+      ac = ProfileCategorization.create!(:category => c2, :profile => p)
+      ac = ProfileCategorization.create!(:category => c3, :profile => p)
+    end
+  end
+
+  should 'remove all instances for a given profile' do
+    c1 = Category.create!(:name => 'c1', :environment => Environment.default)
+    c2 = c1.children.create!(:name => 'c2', :environment => Environment.default)
+    c3 = c1.children.create!(:name => 'c3', :environment => Environment.default)
+
+    p = create_user('testuser').person
+
+    ac = ProfileCategorization.create!(:category => c2, :profile => p)
+    ac = ProfileCategorization.create!(:category => c3, :profile => p)
+
+    assert_difference ProfileCategorization, :count, -3 do
+      ProfileCategorization.remove_all_for(p)
+    end
+  end
+
 end
diff --git a/test/unit/profile_test.rb b/test/unit/profile_test.rb
index cf631f9..1cd265e 100644
--- a/test/unit/profile_test.rb
+++ b/test/unit/profile_test.rb
@@ -540,6 +540,46 @@ class ProfileTest < Test::Unit::TestCase
     assert profile.enabled?
   end
 
+  should 'categorize in the entire category hierarchy' do
+    c1 = Category.create!(:environment => Environment.default, :name => 'c1')
+    c2 = c1.children.create!(:environment => Environment.default, :name => 'c2')
+    c3 = c2.children.create!(:environment => Environment.default, :name => 'c3')
+
+    profile = create_user('testuser').person
+    profile.add_category(c3)
+
+
+    assert_equal [c3], profile.categories(true)
+    assert_equal [profile], c2.people(true)
+
+    assert_includes c3.people(true), profile
+    assert_includes c2.people(true), profile
+    assert_includes c1.people(true), profile
+  end
+
+  should 'redefine the entire category set at once' do
+    c1 = Category.create!(:environment => Environment.default, :name => 'c1')
+    c2 = c1.children.create!(:environment => Environment.default, :name => 'c2')
+    c3 = c2.children.create!(:environment => Environment.default, :name => 'c3')
+    c4 = c1.children.create!(:environment => Environment.default, :name => 'c4')
+    profile = Profile.create!(:name => 'my test profile', :identifier => 'mytestprofile')
+
+    profile.add_category(c4)
+
+    profile.category_ids = [c2,c3].map(&:id)
+
+    assert_equivalent [c2, c3], profile.categories(true)
+  end
+
+  should 'be able to create an profile already with categories' do
+    c1 = Category.create!(:environment => Environment.default, :name => 'c1')
+    c2 = Category.create!(:environment => Environment.default, :name => 'c2')
+
+    profile = Profile.create!(:name => 'my test profile', :identifier => 'mytestprofile', :category_ids => [c1.id, c2.id])
+
+    assert_equivalent [c1, c2], profile.categories(true)
+  end
+
   private
 
   def assert_invalid_identifier(id)
--
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