Merge pull request #63 from Jhut89/code_cleanup

add ext-json to composer.json

Author: Jhut89

composer.json

@@ -16,7 +16,8 @@
     },
     "require": {
         "php": ">=5.5.0",
-        "ext-curl": "*"
+        "ext-curl": "*",
+        "ext-json": "*"
     },
     "homepage": "https://github.com/Jhut89/Mailchimp-API-3.0-PHP",
     "require-dev": {