Will make students managing calendar able to reserve app

fixes COMMS-1857

Test Plan
1. Enable the permission "Course Calendar -
add/edit/delete events" for the student role
2. As the teacher, create an appointment group in your course
3. As a student, try to reserve a time slot, notice that the
 "reserve" button and comment box are now rendered

Change-Id: I1f67b7ee30562ef7346e18c8c819a39f339f1f5f
Reviewed-on: https://gerrit.instructure.com/179586
Tested-by: Jenkins
QA-Review: Steven Burnett <sburnett@instructure.com>
Product-Review: Steven Burnett <sburnett@instructure.com>
Reviewed-by: Landon Gilbert-Bland <lbland@instructure.com>
Reviewed-by: James Williams <jamesw@instructure.com>

app/coffeescripts/calendar/ShowEventDetailsDialog.js

@@ -246,9 +246,9 @@ export default class ShowEventDetailsDialog {
     const params = $.extend(true, {}, this.event, {
       can_reserve: this.event.object && this.event.object.reserve_url
     })
-    // For now, assume that if someone has the ability to create appointment groups
-    // in a course, they shouldn't also be able to sign up for them.
-    if (this.event.contextInfo.can_create_appointment_groups) {
+
+    // For now used to eliminate the ability of teachers and tas seeing the excess reserveration link
+    if (!this.event.contextInfo.can_make_reservation) {
       params.can_reserve = false
     }
 

app/controllers/calendars_controller.rb

@@ -68,6 +68,7 @@ class CalendarsController < ApplicationController
         :can_create_assignments => context.respond_to?("assignments") && Assignment.new.tap{|a| a.context = context}.grants_right?(@current_user, session, :create),
         :assignment_groups => context.respond_to?("assignments") ? context.assignment_groups.active.pluck(:id, :name).map {|id, name| { :id => id, :name => name } } : [],
         :can_create_appointment_groups => ag_permission,
+        :can_make_reservation => context.grants_right?(@current_user, :participate_as_student),
         :can_update_todo_date => context.grants_right?(@current_user, session, :manage),
         :can_update_discussion_topic => context.grants_right?(@current_user, session, :moderate_forum),
         :can_update_wiki_page => context.grants_right?(@current_user, session, :manage_wiki),

spec/controllers/calendars_controller_spec.rb

@@ -43,6 +43,14 @@ describe CalendarsController do
       expect(assigns[:contexts][1]).to eql(@course)
     end
 
+    it "only enrolled students can make reservations" do
+      course_event
+      get 'show', params: {:user_id => @user.id}
+      expect(response).to be_successful
+      expect(assigns[:contexts_json][0][:can_make_reservation]).to eql(false)
+      expect(assigns[:contexts_json][1][:can_make_reservation]).to eql(true)
+    end
+
     it "js_env DUE_DATE_REQUIRED_FOR_ACCOUNT is true when AssignmentUtil.due_date_required_for_account? == true" do
       allow(AssignmentUtil).to receive(:due_date_required_for_account?).and_return(true)
       get 'show', params: {:user_id => @user.id}