db.to_dataframe: explicitly recommand providing pd.df (#1450)
db.to_dataframe: explicitly recommand providing pd.df (#1450)

Signed-off-by: Nir Izraeli <951d3baf13044c36e30f2d4c12a71fcee2f30c1c@gmail.com>
chrisbarber/dask,jcrist/dask,ContinuumIO/dask,jakirkham/dask,cowlicks/dask,cpcloud/dask,jcrist/dask,mraspaud/dask,dask/dask,blaze/dask,mraspaud/dask,blaze/dask,mrocklin/dask,dask/dask,mrocklin/dask,ContinuumIO/dask,jakirkham/dask,gameduell/dask