Adding the dependency in package.json

package.json

@@ -8,7 +8,7 @@
     ],
     "name": "babylonjs",
     "description": "Babylon.js is a JavaScript 3D engine based on webgl.",
-    "version": "3.1.0-alpha3.4",
+    "version": "3.1.0-alpha3.5",
     "repository": {
         "type": "git",
         "url": "https://github.com/BabylonJS/Babylon.js.git"
@@ -58,7 +58,9 @@
         "webgl"
     ],
     "license": "Apache-2.0",
-    "dependencies": {},
+    "dependencies": {
+        "cannon": "0.6.2"
+    },
     "engines": {
         "node": "*"
     },