Correction in command to add new user and switch user

1.Add user
The current command didn't take care of setting the password for
new user. Added below command which takes care of the missing part
sudo useradd -s /bin/bash -d /home/<user> -m -G sudo <user>
sudo passwd <user>
where,
-s /bin/bash – Set /bin/bash as login shell of the new account
-d /home/<user> – Set /home/<user> as home directory of the new user account
-m – Create the user’s home directory
-G sudo – Make sure <user> can sudo i.e. give admin access to the new account

2.Switch user
current: sudo su -c <user>
corrected one: sudo su - <user>

Change-Id: I83355cd92aace4d6a62fd0a2427713a1369f86c7
Signed-off-by: Poornima <poornima.y.n@intel.com>

doc/source/developer_resources/build_guide.rst

@@ -71,9 +71,9 @@ Installation requirements and dependencies
 
    ::
 
-     sudo useradd -m -d /home/<user> <user>
-     sudo sh -c "echo '<user> ALL=(ALL:ALL) ALL' >> /etc/sudoers"
-     sudo su -c <user>
+     sudo useradd -s /bin/bash -d /home/<user> -m -G sudo <user>
+     sudo passwd <user>
+     sudo su - <user>
 
 
 #. Set up Git.