Merge pull request #761 from FridaTveit/AddBlurb

Add blurb to config.json

config.json

 {
   "language": "Java",
   "active": true,
+  "blurb": "Java is a very widely used Object Oriented programming language. It's safe, simple to use and portable so that you can \"write once, run anywhere\".",
   "exercises": [
     {
       "uuid": "f77dc7e3-35a8-4300-a7c8-2c1765e9644d",