Programatically adding a sharepoint group and RoleAssignment

Scenario:
Dont ask me why but I was asked to create sharepoint group programatically. Also on top of it attach that group to a particular Roledefinition (i.e "Members" )

Solution:
Object Model , my favorite

Code:

 private void AddGroup(SPWeb web, string GroupName, SPUser groupOwner, string GroupDescription, string roleDefinitionName)
{
   SPGroup    oGroup = GetSiteGroup(web, GroupName);

   if (oGroup == null)
   {
     web.SiteGroups.Add(GroupName, groupOwner, null, GroupDescription);
     oGroup = GetSiteGroup(web, GroupName);
   }
            
   // Create the role assignment object
   SPRoleAssignment oRoleAssignment = new SPRoleAssignment(oGroup);

   // Add the role definition to the role assignemnt. 
  // This will assign the specific permission to the security principal for this role assignemnt.
oRoleAssignment.RoleDefinitionBindings.Add(web.RoleDefinitions[roleDefinitionName)]);

  // Now we need to add the role assignment to the web
  web.RoleAssignments.Add(oRoleAssignment);

  // Now update the web
  web.Update();
}

  private SPGroup GetSiteGroup(SPWeb web, string name)       
  {           
    foreach (SPGroup group in web.SiteGroups)               
    if (group.Name.ToLower() == name.ToLower())                    
      return group;           
      
      return null;        
}

Article: