diff --git a/slate/slate.py b/slate/slate.py
index d24c987..f571257 100644
--- a/slate/slate.py
+++ b/slate/slate.py
@@ -35,9 +35,11 @@ else:
 
 class Slate():
     def __init__(self, runners):
-        self.runners = runners
-        self.runners['printConfig'] = Print_Config_Runner
-        self.runners['pdb'] = PDB_Runner
+        self.runners = {
+            'printConfig': Print_Config_Runner,
+            'pdb': PDB_Runner,
+        }
+        self.runners.update(runners)
         self._version = False
 
     def load_config(self, filename, name):