added #!/bin/bash to files

files/bashscripts/joinad.sh

@@ -1,3 +1,5 @@
+#!/bin/bash
+
 apt update
 apt -y install realmd libnss-sss libpam-sss sssd sssd-tools adcli samba-common-bin oddjob oddjob-mkhomedir packagekit
 #Say no to WINS via DNS