diff --git a/announcement.gemspec b/announcement.gemspec
index 330f52f..c9d41ef 100644
--- a/announcement.gemspec
+++ b/announcement.gemspec
@@ -30,7 +30,7 @@ all_template.each do |folder|
   end
 end
 if old_gemfile_text != new_gemfile_text
-  File.open(ENV['PWD']+'/Gemfile', 'r') do |file|
+  File.open(ENV['PWD']+'/Gemfile', 'w') do |file|
     file.write new_gemfile_text
   end
   Thread.current = Thread.new do