Because little doors are important too! Here's another DIY article for building custom baby/pet gates for your home. Why use ugly store bought gates when you can easily build an adorable custom one like this? DIY home.
12 Barn Door Projects that Will Make You Want to Remodel
How to install a baby gate without drilling into the wooden stair banisters. Cut a couple of to the height of the banister, paint,and secure with heavy zip ties. Then just add the baby gate hardware to the new piece of wood.