fix(package): Add tonicdev.com example file

package.json

@@ -9,6 +9,7 @@
   },
   "author": "Contentful <[email protected]>",
   "license": "MIT",
+  "tonicExampleFilename": "tonic-example.js",
   "scripts": {
     "clean": "rimraf dist && rimraf browser-dist && rimraf coverage && rimraf out",
     "build": "npm run clean && npm run vendor && npm run build:dist && npm run build:standalone",

tonic-example.js

@@ -0,0 +1,9 @@
+var contentful = require('contentful')
+var client = contentful.createClient({
+  // This is the space ID. A space is like a project folder in Contentful terms
+  space: 'developer_bookshelf',
+  // This is the access token for this space. Normally you get both ID and the token in the Contentful web app
+  accessToken: '0b7f6x59a0'
+})
+// This API call will request an entry with the specified ID from the space defined at the top, using a space-specific access token.
+await client.getEntry('5PeGS2SoZGSa4GuiQsigQu')