For openSUSE Leap 15.2 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mschnitzer/openSUSE_Leap_15.2/home:mschnitzer.repo
zypper refresh
zypper install rubygem-fullcalendar-rails
For openSUSE Leap 15.1 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mschnitzer/openSUSE_Leap_15.1/home:mschnitzer.repo
zypper refresh
zypper install rubygem-fullcalendar-rails
For openSUSE Leap 15.0 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mschnitzer/openSUSE_Leap_15.0/home:mschnitzer.repo
zypper refresh
zypper install rubygem-fullcalendar-rails
For openSUSE Factory run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mschnitzer/openSUSE_Factory/home:mschnitzer.repo
zypper refresh
zypper install rubygem-fullcalendar-rails