diff --git a/config/deploy/production.rb b/config/deploy/production.rb
index 718752f..6302495 100644
--- a/config/deploy/production.rb
+++ b/config/deploy/production.rb
@@ -1,3 +1,4 @@
+require 'yaml'
 # server-based syntax
 # ======================
 # Defines a single server with a list of roles and multiple properties.
@@ -15,7 +16,7 @@ end
 set :deploy_to, config.fetch("deploy_to")
 set :branch, "production"
 
-if config.has_key?(:keep_releases)
+if config.has_key?("keep_releases")
   set :keep_releases, config.fetch("keep_releases").to_i
 end
 
diff --git a/config/deploy/staging.rb b/config/deploy/staging.rb
index ec380ca..ed373a4 100644
--- a/config/deploy/staging.rb
+++ b/config/deploy/staging.rb
@@ -16,7 +16,7 @@ end
 set :deploy_to, config.fetch("deploy_to")
 set :branch, "staging"
 
-if config.has_key?(:keep_releases)
+if config.has_key?("keep_releases")
   set :keep_releases, config.fetch("keep_releases").to_i
 end