diff --git a/app/models/user.rb b/app/models/user.rb
index 8a9a746..d02baa0 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -18,11 +18,13 @@ class User < ActiveRecord::Base
 
   attr_accessible :nickname, :email, :name
 
-  scope :for_credentials, -> (credentials) {
+  def self.for_credentials(credentials)
     where(provider: credentials.provider, uid: credentials.uid).first
-  }
+  end
 
-  scope :for_email, -> (email) { where(email: email).first }
+  def self.for_email(email)
+    where(email: email).first
+  end
 
   def to_param
     nickname
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 2d5b4c9..90c6ec7 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -14,6 +14,42 @@ describe User do
     end
   end
 
+  describe '.for_credentials' do
+    subject { described_class.for_credentials(credentials) }
+
+    let!(:user) { create(:user, provider: 'twitter', uid: '1') }
+
+    context "when there is matching record" do
+      let(:credentials) { double('credentials', provider: 'twitter', uid: '1') }
+
+      it { should eq(user) }
+    end
+
+    context "when there isn't matching record" do
+      let(:credentials) { double('credentials', provider: 'twitter', uid: '2') }
+
+      it { should be(nil) }
+    end
+  end
+
+  describe '.for_email' do
+    subject { described_class.for_email(email) }
+
+    let!(:user) { create(:user, email: 'foo@bar.com') }
+
+    context "when there is matching record" do
+      let(:email) { 'foo@bar.com' }
+
+      it { should eq(user) }
+    end
+
+    context "when there isn't matching record" do
+      let(:email) { 'qux@bar.com' }
+
+      it { should be(nil) }
+    end
+  end
+
   describe '#add_user_token' do
     let(:user) { build(:user) }