Require predis/predis as dev dependency

composer.json

@@ -40,7 +40,8 @@
         "barryvdh/laravel-debugbar": "~3.0",
         "orchestra/testbench": "^3.5",
         "league/flysystem-aws-s3-v3": "^1.0",
-        "league/commonmark": "^0.15.4"
+        "league/commonmark": "^0.15.4",
+        "predis/predis": "^1.1"
     },
     "autoload": {
         "classmap": [