Migrate composer updater

lib/SlackBuilder/Trans.hs

@@ -5,6 +5,7 @@ module SlackBuilder.Trans
 import Control.Monad.Trans.Reader (ReaderT(..))
 import SlackBuilder.Config
 import Control.Monad.IO.Class (MonadIO(..))
+import Control.Monad.Catch (MonadCatch(..), MonadThrow(..))
 
 newtype SlackBuilderT a = SlackBuilderT
     { runSlackBuilderT :: ReaderT Settings IO a
@@ -27,3 +28,12 @@ instance Monad SlackBuilderT
 instance MonadIO SlackBuilderT
   where
     liftIO = SlackBuilderT . liftIO
+
+instance MonadThrow SlackBuilderT
+  where
+    throwM = SlackBuilderT . throwM
+
+instance MonadCatch SlackBuilderT
+  where
+    catch (SlackBuilderT action) handler =
+        SlackBuilderT $ catch action $ runSlackBuilderT . handler