recursive data fetch in laravel query

I have the table user which has user_name and manager name.I want to get the user name for who have manager ='test'.I want to get the user who are having ramya as manager and reportee's reportee

 users table 
SNO user_name   manager
1    vani        Ramya
2    ramya       geetha
3    priya       ramya
4    mani        ramya
5    latha       vani
6.   hema        Anitha 

    project table
   code   name        owner   customer_code
   UTC-p1 project 1    latha   UTC-C-p1 
   GST-p1 project 2    latha   GST-c-p1 
   UTC-p1 project 3    vani    UTC-C-p2     
   UTC-p1 project 4    bala    UTC-C-p3



customer table 
    name         code
     UTC        UTC-C-p1
     GST        GST-c-p1

the customer name is 'UTC' and I want to get the name ramya and ramya's reportee vani,priya and mani and get latha who is having vani as manager who is having ramya as manager. I want to get ramya,vani,priya,mani and latha and fetch the project only belongs to her hierarchy based on customer code.

$users = DB::table('users as a')
        ->select('a.user_name')
        ->leftJoin('users as b', 'a.manager', '=', 'b.user_name')
        ->where('a.user_name','Ramya')
        ->orwhere('a.manager','Ramya')
        ->orwhere('b.manager','Ramya')
        ->get(); //returns(ramya,vani,priya,mani and latha)

get the get the project name 'project 1' which is related to her hierarchy

via Chebli Mohamed