add user in samba server

# smbpasswd -a linuxsir
New SMB password:
Retype new SMB password:
# ls  /etc/samba
gdbcommands  smb.conf  smb.conf.bak  smbpasswd
# groups  linuxsir
linuxsir : linuxsir my_test_group1
root@debian:/home/debian# cat /etc/group
root:x:0:
sambashare:x:119:
root@debian:/home/debian#
# cat /etc/samba/smbpasswd

I have add user linuxsir in samba with a password.

1.Why linuxsir is still not in the group sambashare?

2.Why is there nothing in the file /etc/samba/smbpasswd?