updated plantcv pipeline script to create db as default and append if db exists. With -c create flag an existing DB is now overwritten.
updated plantcv pipeline script to create db as default and append if
db exists. With -c create flag an existing DB is now overwritten.

AntonSax/plantcv,stiphyMT/plantcv,jshoyer/plantcv,AntonSax/plantcv,danforthcenter/plantcv,jshoyer/plantcv,danforthcenter/plantcv,stiphyMT/plantcv,stiphyMT/plantcv,danforthcenter/plantcv