app.config file values used with enums

In a C# 2008 application I am trying to determine how to correlate values from an app.config file with an enum value. 
 Right now in this C# application the user roles are hard-coded and the hardcoded values are used in an enumeration based upon user roles.
The enumeration looks like the following:public enum ERole  {
  User = 0, Manager  = 1,  Administrator = 2, read =3}
switch (eRole)  {
case User: 
return IsInGroup(ConfigurationManager.AppSettings["user"]); 
case Read: 
return IsInGroup(ConfigurationManager.AppSettings["read"]);
default: 
return false;
  }

 Now I am changing the code to use values from the app.config file instead of using hard-coded values.

The app.config file looks like the following:
  < appSettings>
 
 
 
 
  switch (eRole)  {
case User: 
return IsInGroup(ConfigurationManager.AppSettings["user"]); 
case Read: 
return IsInGroup(ConfigurationManager.AppSettings["read"]);
default: 
return false;
  }

 However my problem is, how should I change the enum listed above so I do not use the hard-coded value for User, Manager, Administrator, and read? I could possibly change the switch statement.