add extensions to the spec json schemas

extensions/0.1.0/info.json

@@ -0,0 +1,16 @@
+{
+    "type": "object",
+    "additionalProperties": false,
+    "properties": {
+        "x-twitter": {
+            "type": "string",
+            "description": "This extension allows you to provide the Twitter username of the account representing the team/company of the API.",
+            "example": [
+                "sambhavgupta75",
+                "AsyncAPISpec"
+            ]
+        }
+    },
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "$id": "http://asyncapi.com/extensions/0.1.0/info.json"
+}

tools/bundler/index.js

@@ -4,10 +4,12 @@ const traverse = require('json-schema-traverse');
 const { url } = require('inspector');
 const definitionsDirectory = path.resolve(__dirname, '../../definitions');
 const bindingsDirectory = path.resolve(__dirname, '../../bindings');
+const extensionsDirectory = path.resolve(__dirname, '../../extensions');
 const outputDirectory = path.resolve(__dirname, '../../schemas');
 const JSON_SCHEMA_PROP_NAME = 'json-schema-draft-07-schema';
 console.log(`Looking for separate definitions in the following directory: ${definitionsDirectory}`);
 console.log(`Looking for binding version schemas in the following directory: ${bindingsDirectory}`);
+console.log(`Looking for extension version schemas in the following directory: ${extensionsDirectory}`);
 console.log(`Using the following output directory: ${outputDirectory}`);
 
 // definitionsRegex is used to transform the name of a definition into a valid one to be used in the -without-$id.json files.