Allow admins to become teachers

app/core/Tracker.coffee

@@ -181,6 +181,7 @@ module.exports = class Tracker extends CocoClass
     ga? 'send', 'timing', category, variable, duration, label
 
   updateRole: ->
+    return if me.isAdmin()
     return unless me.isTeacher()
     return require('core/services/segment')() unless @segmentLoaded
     @identify()

app/models/User.coffee

@@ -92,7 +92,6 @@ module.exports = class User extends CocoModel
     Boolean((utils.getQueryVariable('dev', false) or me.isTeacher()) and utils.getQueryVariable('course', false))
 
   setRole: (role, force=false) ->
-    return if me.isAdmin()
     oldRole = @get 'role'
     return if oldRole is role or (oldRole and not force)
     @set 'role', role