diff --git a/app/models/project.rb b/app/models/project.rb
index b157c29..a6f4e3b 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -7,6 +7,8 @@ class Project < ActiveRecord::Base
     timestamps
   end
 
+  has_many :stories, :dependent => :destroy
+
   # --- Permissions --- #
 
   def create_permitted?
diff --git a/app/models/story.rb b/app/models/story.rb
index 41e2761..1d3b609 100644
--- a/app/models/story.rb
+++ b/app/models/story.rb
@@ -9,6 +9,10 @@ class Story < ActiveRecord::Base
     timestamps
   end
 
+  belongs_to :project
+
+  has_many :tasks, :dependent => :destroy
+
   # --- Permissions --- #
 
   def create_permitted?
diff --git a/app/models/task.rb b/app/models/task.rb
index 9a30863..f79516b 100644
--- a/app/models/task.rb
+++ b/app/models/task.rb
@@ -7,6 +7,11 @@ class Task < ActiveRecord::Base
     timestamps
   end
 
+  belongs_to :story
+
+  has_many :task_assignments, :dependent => :destroy
+  has_many :users, :through => :task_assignments
+
   # --- Permissions --- #
 
   def create_permitted?
diff --git a/app/models/task_assignment.rb b/app/models/task_assignment.rb
index b5c2ac1..b420c68 100644
--- a/app/models/task_assignment.rb
+++ b/app/models/task_assignment.rb
@@ -6,6 +6,9 @@ class TaskAssignment < ActiveRecord::Base
     timestamps
   end
 
+  belongs_to :user
+  belongs_to :task
+
   # --- Permissions --- #
 
   def create_permitted?
diff --git a/app/models/user.rb b/app/models/user.rb
index 248f9fd..6c79ebe 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -9,6 +9,11 @@ class User < ActiveRecord::Base
     timestamps
   end
 
+  validates_presence_of :name
+
+  has_many :task_assignments, :dependent => :destroy
+  has_many :tasks, :through => :task_assignments
+
   # This gives admin rights and an :active state to the first sign-up.
   # Just remove it if you don't want that
   before_create do |user|