Added Flutter (#150)

communities.json

@@ -642,12 +642,12 @@
       "githubUrl": "https://github.com/gatsbyjs/gatsby"
     },
     {
-      "logo": "dvc.svg",
-      "title": "DVC",
-      "quote": "We choose Discord, because it is a great platform - open, reliable, easy-to-access. With Discord we can focus on growing our community without any limitations. ",
-      "quoteSourceUrl": "https://dvc.org/",
-      "inviteCode": "dvwXA2N",
-      "githubUrl": "https://github.com/iterative/dvc"
+      "logo": "flutter.png",
+      "title": "Flutter",
+      "quote": "Talk to other Flutter developers about everything Flutter-related, and share useful resources.",
+      "quoteSourceUrl": "https://flutter.dev/community",
+      "inviteCode": "N7Yshp4",
+      "githubUrl": "https://github.com/flutter/flutter"
     }
   ]
 }