ERROR: ActiveRecord oracle_enhanced adapter could not load ruby-oci8 library. Please install ruby-oci8 gem.

If you are facing an error on ubuntu while connecting oracle even though you have installed ruby-oci8 and activerecord-oracle_enhanced_adapter you need install following library.

Problem:

ERROR: ActiveRecord oracle_enhanced adapter could not load ruby-oci8 library. Please install ruby-oci8 gem.

Solution:
sudo apt-get install libaio1


I hope this should work for you.