Update composer.json

Only autoload the tests namespace in dev.

composer.json

@@ -19,7 +19,11 @@
             "database"
         ],
         "psr-4": {
-            "App\\": "app/",
+            "App\\": "app/"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
             "Tests\\": "tests/"
         }
     },