Grating user webservd permission to create files on a directory owned by bob. Note that according to the initial setup, webservd won't be able to do that unless additional permission is granted.
But be aware!
This will also allow webservd to delete all files on dir1! (and even dir1 itself!)
webservd@box-01:/home/bob/dir1 $ touch file1
touch: cannot create file1: Permission denied
bob@box-01:~ $ chmod A0=user:webservd:rwxaRcs:allow dir1
bob@box-01:~ $ ll -dV dir1
drwxr-xr-x+ 2 bob staff 2 Jun 20 09:01 dir1
user:webservd:rwx---a-R-c--s:-------:allow
owner@:rwxp-DaARWcCos:-------:allow
group@:r-x---a-R-c--s:-------:allow
everyone@:r-x---a-R-c--s:-------:allow
webservd@box-01:/home/bob/dir1 $ touch file1
webservd@box-01:/home/bob/dir1 $ ll
total 1
-rw-r--r-- 1 webservd webservd 0 Jun 20 09:13 file1
webservd@box-01:/home/bob/dir1 $ rm file2
rm: file2: override protection 640 (yes/no)? y
webservd@box-01:/home/bob/dir1 $ ll
total 0
