diff --git a/app/models/asciicast.rb b/app/models/asciicast.rb
index 58cb7bf..b69efc2 100644
--- a/app/models/asciicast.rb
+++ b/app/models/asciicast.rb
@@ -13,6 +13,11 @@ class Asciicast < ActiveRecord::Base
 
   attr_reader :description
 
+  def self.assign_user(user_token, user)
+    where(:user_id => nil, :user_token => user_token).
+    update_all(:user_id => user.id, :user_token => nil)
+  end
+
   def meta=(file)
     data = JSON.parse(file.tempfile.read)
 
diff --git a/spec/models/asciicast_spec.rb b/spec/models/asciicast_spec.rb
index cba5aad..708c899 100644
--- a/spec/models/asciicast_spec.rb
+++ b/spec/models/asciicast_spec.rb
@@ -5,6 +5,23 @@ describe Asciicast do
     Factory.build(:asciicast).should be_valid
   end
 
+  describe '.assign_user' do
+    let(:user) { Factory(:user) }
+    let(:token) { 'token' }
+    let!(:asciicast) { Factory(:asciicast, :user => nil, :user_token => token) }
+
+    subject { Asciicast.assign_user(token, user) }
+
+    it 'returns number of updated records' do
+      subject.should == 1
+    end
+
+    it 'assigns user to matching asciicasts' do
+      subject
+      asciicast.reload.user.should == user
+    end
+  end
+
   describe '#save' do
     let(:asciicast) { Factory.build(:asciicast, :user => user) }