Added url as a property

Author: zubairov

component.json

@@ -7,6 +7,11 @@
       "title": "Read CSV file from URL",
       "type": "polling",
       "fields": {
+        "url" : {
+          "label": "CSV URL",
+          "required": true,
+          "viewClass": "TextFieldView"
+        },
         "reader": {
           "viewClass": "CSVReadView"
         }