Update composer.json

Author: jakewhiteley

composer.json

@@ -5,5 +5,10 @@
     "version": "1.0.0",
     "require": {
         "php": "^5.4 || ^7.0"
+    },
+    "autoload": {
+        "psr-0": {
+            "PhpSets": "/"
+        }
     }
 }