diff --git a/lib/fizzbuzz.rb b/lib/fizzbuzz.rb
index 4746a88..f9a304d 100644
--- a/lib/fizzbuzz.rb
+++ b/lib/fizzbuzz.rb
@@ -1,6 +1,8 @@
 class Fizzbuzz
   def calculate number
-    if number % 3 == 0 && number % 5 == 0
+    if number.to_s.include? '7'
+      'GitHub'
+    elsif number % 3 == 0 && number % 5 == 0
       'fizzbuzz'
     elsif number % 3 == 0
       'fizz'
diff --git a/spec/fizzbuzz_spec.rb b/spec/fizzbuzz_spec.rb
index 93a63e6..f0a9b7a 100644
--- a/spec/fizzbuzz_spec.rb
+++ b/spec/fizzbuzz_spec.rb
@@ -6,6 +6,12 @@
     it { subject.calculate(1).should eq 1 }
     it { subject.calculate(2).should eq 2 }
   end
+  context 'GitHub number' do
+    it { subject.calculate(17).should eq 'GitHub' }
+    it { subject.calculate(27).should eq 'GitHub' }
+    it { subject.calculate(75).should eq 'GitHub' }
+    it { subject.calculate(77).should eq 'GitHub' }
+  end
   context 'Fizz number' do
     it { subject.calculate(3).should eq 'fizz' }
     it { subject.calculate(6).should eq 'fizz' }