hotfix

app/controllers/assignments_controller.rb

@@ -57,7 +57,7 @@ class AssignmentsController < ApplicationController
         @user.assignments.each do |assignment|
           session = assignment.session
           other_users = session.assignments.map { |a| a.user.name }
-          other_users = other_users - @user.name
+          other_users = other_users - [ @user.name ]
 
           event = Icalendar::Event.new
           event.dtstart = Icalendar::Values::DateTime.new(session.starts_at, tzid: session.starts_at.zone)