user id isn't necessary since baby belongs to user

app/models/stat.rb

@@ -1,6 +1,5 @@
 class Stat < ActiveRecord::Base
-  belongs_to :user
   belongs_to :baby
 
-  validates_presence_of :user_id, :baby_id
+  validates_presence_of :baby_id
 end

db/migrate/20120226174811_remove_user_id_from_stats.rb

@@ -0,0 +1,5 @@
+class RemoveUserIdFromStats < ActiveRecord::Migration
+  def change
+    remove_column :stats, :user_id
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20120212193024) do
+ActiveRecord::Schema.define(:version => 20120226174811) do
 
   create_table "babies", :force => true do |t|
     t.string   "name"
@@ -27,7 +27,6 @@
   end
 
   create_table "stats", :force => true do |t|
-    t.integer  "user_id"
     t.integer  "baby_id"
     t.float    "height_in_meters"
     t.integer  "age_months"

spec/models/stat_spec.rb

@@ -18,36 +18,18 @@
   context "given valid attributes" do
     it "should save the stats" do
       stats = FactoryGirl.build(:stat)
-      stats.user = user
       stats.baby = baby
       stats.valid?.should be_true
       stats.save.should be_true
     end
   end
 
-  context "given no user" do
-    it "should not save the stats" do
-      stats = FactoryGirl.build(:stat)
-      stats.baby = baby
-      stats.valid?.should be_false
-      stats.save.should be_false
-    end
-  end
-
   context "given no baby" do
     it "should not save the stats" do
       stats = FactoryGirl.build(:stat)
-      stats.user = user
       stats.valid?.should be_false
       stats.save.should be_false
     end
   end
 
-  context "given no baby and no user" do
-    it "should not save the stats" do
-      stats = FactoryGirl.build(:stat)
-      stats.valid?.should be_false
-      stats.save.should be_false
-    end
-  end
 end