Ignore or suppress .ipynb_checkpoint/**.sql files

[jordanperr]

When running dbt seed (dag compilation), sometimes you'll get the following error:

Compilation Error in model stg_entr_tag_list-checkpoint (models/staging/.ipynb_checkpoints/stg_entr_tag_list-checkpoint.sql)
Model 'model.entr_warehouse.stg_entr_tag_list-checkpoint' (models/staging/.ipynb_checkpoints/stg_entr_tag_list-checkpoint.sql) depends on a node named 'entr_tag_list' which was not found

This is caused by checkpointed files from Jupyter Hub. Current solution is to delete the .ipynb_checkpoint directories.