Add spm support

Author: afc163

README.md

@@ -16,6 +16,8 @@ Decouple the DOM events from expensive functions.
 
     $ bower install decouple
 
+    $ spm install decouple
+
     $ component install pazguille/decouple
 
 ## Usage

package.json

@@ -25,5 +25,8 @@
     "events",
     "dom events"
   ],
-  "license": "MIT"
+  "license": "MIT",
+  "spm": {
+    "main": "index.js"
+  }
 }