fix: Set hub_url in Hub Settings

- add patch to set the value
diff --git a/erpnext/hub_node/api.py b/erpnext/hub_node/api.py
index 441d30b..74219da 100644
--- a/erpnext/hub_node/api.py
+++ b/erpnext/hub_node/api.py
@@ -180,9 +180,9 @@
 
 	# read-only connection
 	if read_only:
-		hub_connection = FrappeClient(frappe.conf.hub_url)
+		hub_url = frappe.db.get_single_value('Hub Settings', 'hub_url')
+		hub_connection = FrappeClient(hub_url)
 		return hub_connection
 
-
 def get_field_mappings():
 	return []
diff --git a/erpnext/hub_node/doctype/hub_settings/hub_settings.js b/erpnext/hub_node/doctype/hub_settings/hub_settings.js
index be8fe21..03314bb 100644
--- a/erpnext/hub_node/doctype/hub_settings/hub_settings.js
+++ b/erpnext/hub_node/doctype/hub_settings/hub_settings.js
@@ -1,8 +1,4 @@
 frappe.ui.form.on("Hub Settings", {
-	refresh: function(frm) {
-		frm.disable_save();
-	},
-
 	onload_post_render: function(frm) {
 		if(frm.get_field("unregister_from_hub").$input)
 			frm.get_field("unregister_from_hub").$input.addClass("btn-danger");
diff --git a/erpnext/hub_node/doctype/hub_settings/hub_settings.json b/erpnext/hub_node/doctype/hub_settings/hub_settings.json
index 30eaa0b..e230515 100644
--- a/erpnext/hub_node/doctype/hub_settings/hub_settings.json
+++ b/erpnext/hub_node/doctype/hub_settings/hub_settings.json
@@ -19,6 +19,39 @@
    "bold": 0, 
    "collapsible": 0, 
    "columns": 0, 
+   "default": "https://hubmarket.org", 
+   "fieldname": "hub_url", 
+   "fieldtype": "Data", 
+   "hidden": 0, 
+   "ignore_user_permissions": 0, 
+   "ignore_xss_filter": 0, 
+   "in_filter": 0, 
+   "in_global_search": 0, 
+   "in_list_view": 0, 
+   "in_standard_filter": 0, 
+   "label": "Hub URL", 
+   "length": 0, 
+   "no_copy": 0, 
+   "permlevel": 0, 
+   "precision": "", 
+   "print_hide": 0, 
+   "print_hide_if_no_value": 0, 
+   "read_only": 0, 
+   "remember_last_selected_value": 0, 
+   "report_hide": 0, 
+   "reqd": 0, 
+   "search_index": 0, 
+   "set_only_once": 0, 
+   "translatable": 0, 
+   "unique": 0
+  }, 
+  {
+   "allow_bulk_edit": 0, 
+   "allow_in_quick_entry": 0, 
+   "allow_on_submit": 0, 
+   "bold": 0, 
+   "collapsible": 0, 
+   "columns": 0, 
    "fieldname": "registered", 
    "fieldtype": "Check", 
    "hidden": 0, 
@@ -446,8 +479,8 @@
  "issingle": 1, 
  "istable": 0, 
  "max_attachments": 0, 
- "modified": "2018-08-29 16:56:37.560417", 
- "modified_by": "faris@erpnext.com", 
+ "modified": "2018-08-29 17:46:30.413159", 
+ "modified_by": "Administrator", 
  "module": "Hub Node", 
  "name": "Hub Settings", 
  "name_case": "", 
@@ -480,5 +513,6 @@
  "sort_field": "modified", 
  "sort_order": "DESC", 
  "track_changes": 1, 
- "track_seen": 0
+ "track_seen": 0, 
+ "track_views": 0
 }
\ No newline at end of file
diff --git a/erpnext/hub_node/doctype/hub_settings/hub_settings.py b/erpnext/hub_node/doctype/hub_settings/hub_settings.py
index e112015..7478db9 100644
--- a/erpnext/hub_node/doctype/hub_settings/hub_settings.py
+++ b/erpnext/hub_node/doctype/hub_settings/hub_settings.py
@@ -18,9 +18,7 @@
 		self.site_name = frappe.utils.get_url()
 
 	def get_hub_url(self):
-		if not frappe.conf.hub_url:
-			frappe.throw('hub_url is not set in site_config')
-		return frappe.conf.hub_url
+		return self.hub_url
 
 	def register(self):
 		""" Create a User on hub.erpnext.org and return username/password """
diff --git a/erpnext/patches.txt b/erpnext/patches.txt
index ce69968..6738598 100644
--- a/erpnext/patches.txt
+++ b/erpnext/patches.txt
@@ -559,3 +559,4 @@
 erpnext.patches.v10_0.update_address_template_for_india
 execute:frappe.delete_doc("Page", "hub")
 erpnext.patches.v11_0.reset_publish_in_hub_for_all_items
+erpnext.patches.v11_0.update_hub_url
\ No newline at end of file
diff --git a/erpnext/patches/v11_0/update_hub_url.py b/erpnext/patches/v11_0/update_hub_url.py
new file mode 100644
index 0000000..ced2aaf
--- /dev/null
+++ b/erpnext/patches/v11_0/update_hub_url.py
@@ -0,0 +1,5 @@
+import frappe
+
+def execute():
+	frappe.reload_doc('hub_node', 'doctype', 'Hub Settings')
+	frappe.db.set_value('Hub Settings', 'Hub Settings', 'hub_url', 'https://hubmarket.org')