This image is not ready to work.
Cause of issues with Oracle 12c install on docker I'd have to do manual install on VM and transfer install files.
Dockerfile with this build are available here: https://github.com/MaksymBilenko/docker-oracle-ee-12c/oracle-ee-12c-base

If you would like to use/fork this image you need to perform this steps to make it work:

chown -R oracle:dba /u01/app/oracle
rm -f /u01/app/oracle/product
ln -s /u01/app/oracle-product /u01/app/oracle/product

#Start tnslsnt
su oracle -c "/u01/app/oracle/product/12.2.0/EE/bin/tnslsnr &"

#Create Database:
su oracle -c "$ORACLE_HOME/bin/dbca -silent -createDatabase -templateName General_Purpose.dbc -gdbname xe.oracle.docker -sid xe -responseFile NO_VALUE -characterSet AL32UTF8 -totalMemory 512 -emConfiguration LOCAL -pdbAdminPassword oracle -sysPassword oracle -systemPassword oracle"