diff --git a/db/migrate/20150702195735_create_tasks_categories.rb b/db/migrate/20150702195735_create_tasks_categories.rb
new file mode 100644
index 0000000..1e6ae9c
--- /dev/null
+++ b/db/migrate/20150702195735_create_tasks_categories.rb
@@ -0,0 +1,13 @@
+class CreateTasksCategories < ActiveRecord::Migration
+  def up
+    create_table :proposals_discussion_plugin_task_categories, id: false do |t|
+      t.belongs_to :task, index: true
+      t.belongs_to :category, index: true
+
+    end
+  end
+
+  def down
+    drop_table :proposals_discussion_plugin_task_categories
+  end
+end
diff --git a/lib/proposals_discussion_plugin/proposal_task.rb b/lib/proposals_discussion_plugin/proposal_task.rb
index 2a620fa..76f5b9e 100644
--- a/lib/proposals_discussion_plugin/proposal_task.rb
+++ b/lib/proposals_discussion_plugin/proposal_task.rb
@@ -1,10 +1,16 @@
 class ProposalsDiscussionPlugin::ProposalTask < Task
 
-  has_and_belongs_to_many :proposals_discussion_plugin_task_categories
+  has_and_belongs_to_many :categories,
+  class_name: "ProposalsDiscussionPlugin::TaskCategory",
+  join_table: :proposals_discussion_plugin_task_categories,
+  foreign_key: :task_id,
+  association_foreign_key: :category_id
 
   validates_presence_of :requestor_id, :target_id
   validates_associated :article_object
 
+  validate :require_category
+
   settings_items :name, :type => String
   settings_items :ip_address, :type => String
   settings_items :user_agent, :type => String
@@ -278,4 +284,12 @@ class ProposalsDiscussionPlugin::ProposalTask < Task
   def after_ham!
     self.delay.marked_as_ham
   end
+
+  protected
+
+    def require_category
+      if categories.count == 0 && flagged?
+        errors.add :categories, _( 'Please, select at least one')
+      end
+    end
 end
diff --git a/lib/proposals_discussion_plugin/task_category.rb b/lib/proposals_discussion_plugin/task_category.rb
index b3a0880..d57faaf 100644
--- a/lib/proposals_discussion_plugin/task_category.rb
+++ b/lib/proposals_discussion_plugin/task_category.rb
@@ -1,4 +1,4 @@
 class ProposalsDiscussionPlugin::TaskCategory < Category
 
-  has_and_belongs_to_many :tasks
+  has_and_belongs_to_many :tasks, join_table: :proposals_discussion_plugin_task_categories, foreign_key: :category_id
 end
diff --git a/test/unit/task_category_test.rb b/test/unit/task_category_test.rb
index 7ab16b3..3cf81d4 100644
--- a/test/unit/task_category_test.rb
+++ b/test/unit/task_category_test.rb
@@ -1,6 +1,6 @@
 require_relative '../test_helper'
 
-class TaskCategory < ActiveSupport::TestCase
+class TaskCategoryTest < ActiveSupport::TestCase
 
   def setup
     @person = fast_create(Person)
@@ -12,18 +12,65 @@ class TaskCategory < ActiveSupport::TestCase
   attr_reader :person, :profile, :discussion, :proposal
 
   should 'add a category to a task' do
-    requestor = fast_create(Person)
+
     task_data = {
-      :requestor => requestor,
-      :target => person,
-      :spam => false
+      article: {name: "test proposal", abstract: "teste adadd"},
+      requestor: person,
+      target:  profile,
+      spam: false
     }
 
-    task = Task.create!(task_data)
+    task = ProposalsDiscussionPlugin::ProposalTask.new task_data
+
+    category = ProposalsDiscussionPlugin::TaskCategory.create!(name: 'ProposalTest', environment: Environment.default)
 
-    category = ProposalsDiscussionPlugin::TaskCategory.create!(name: 'ProposalTest', tasks: [task])
+    category.tasks << task;
+    category.save!
 
     assert_equal task.id, category.tasks[0].id
   end
 
+  should 'approve a proposal task without category' do
+
+    task_data = {
+      article: {name: "test proposal", abstract: "teste adadd"},
+      requestor: person,
+      target:  profile,
+      spam: false
+    }
+
+    task = ProposalsDiscussionPlugin::ProposalTask.create! task_data
+    evaluated_by = false
+
+    assert_raise(ActiveRecord::RecordInvalid) { task.flag_accept_proposal evaluated_by }
+
+  end
+
+  should 'approve a proposal task with categories' do
+
+    task_data = {
+      article: {name: "test proposal", abstract: "teste adadd"},
+      requestor: person,
+      target:  profile,
+      spam: false
+    }
+    task = ProposalsDiscussionPlugin::ProposalTask.create! task_data
+    evaluated_by = false
+
+    categories = [
+      { name: 'ProposalTest', environment: Environment.default },
+      { name: 'ProposalTestTwo', environment: Environment.default }
+    ]
+    categories.each do |category|
+        task.categories << ProposalsDiscussionPlugin::TaskCategory.new(category)
+    end
+
+    assert_nothing_raised do
+       task.flag_accept_proposal evaluated_by
+    end
+
+    assert_equal 2, task.categories.count
+
+  end
+
 end
--
libgit2 0.21.2