diff --git a/src/Dockmaster/Types.hs b/src/Dockmaster/Types.hs
index 03f4360..7694be7 100644
--- a/src/Dockmaster/Types.hs
+++ b/src/Dockmaster/Types.hs
@@ -4,6 +4,7 @@ module Dockmaster.Types where
 import Data.Yaml
 import Control.Applicative
 import Data.HashMap.Lazy (HashMap, lookup, member)
+import Data.Monoid (mempty)
 import Prelude hiding (lookup)
 import qualified Data.Text as T