UI-2104: Add warning message when trying to save an empty group:

i18n/en-US.json

@@ -125,7 +125,11 @@
 			"headline": "Caller ID Prepend",
 			"cidNameLabel": "Caller ID Name prefix",
 			"cidNumberLabel": "Caller ID Number prefix"
-		}
+		},
+
+		"__comment": "UI-2104: Adding a warning when adding a group with no endpoints",
+		"__version": "3.22",
+		"emptyEndpointsWarning": "You need to select at least one member to create a group"
 	},
 
 	"devices": {

submodules/groups/groups.js

@@ -279,11 +279,17 @@ define(function(require){
 					groupTemplate.find('#create_group').on('click', function() {
 						if(monster.ui.valid(groupForm)) {
 							var formattedData = self.groupsCreationMergeData(data, groupTemplate);
-							self.groupsCreate(formattedData, function(data) {
-								popup.dialog('close').remove();
 
-								self.groupsRender({ groupId: data.id });
-							});
+							if(!_.isEmpty(formattedData.group.endpoints)) {
+								self.groupsCreate(formattedData, function(data) {
+									popup.dialog('close').remove();
+
+									self.groupsRender({ groupId: data.id });
+								});
+							}
+							else {
+								monster.ui.alert('warning', self.i18n.active().groups.emptyEndpointsWarning);
+							}
 						}
 					});