Index hash with string

1 files changed, 1 insertions, 1 deletions

diff --git a/engine.rb b/engine.rb
index 638a80e..b04e2f2 100644
--- a/engine.rb
+++ b/engine.rb
@@ -38,7 +38,7 @@ class Engine
 
   def state_h
     hash = state_to_hash
-    hash[:checksum] = checksum hash
+    hash['checksum'] = checksum hash
     hash
   end