escape sed replacement strings

[FWDekker]

setting MOMMY_CAREGIVER="a\/b" results in the error sed: -e expression #5, char 20: unterminated `s' command because we do sed -e "s/%%CAREGIVER%%/$caregiver/g", which is unsanitised input into the replacement part of the sed command. therefore, mommy should escape the $caregiver; according to this answer it suffices to escape just a few characters~