In dplyr 0.6.0, a number of databse and SQL functions moved from dplyr to
dbplyr. The generic functions stayed in dplyr (since there is no easy way
to conditionally import a generic from different packages), but many other
SQL and database helper functions moved. If you have written a backend,
these functions generate the code you need to work with both dplyr 0.5.0
dplyr 0.6.0.