Fix SQLAlchemy warning about a cartesian product

[FrostyX]

Fix #72

SAWarning: SELECT statement has a cartesian product between FROM element(s)
"entry" and FROM element "user".  Apply join condition(s) between each
element to resolve.

[xsuchy]

Hmm git-blame say that the code was added in a3e3d8a and the test table has 3 records. And the test do cartesian product and test if search for "chuck" returns 3 records (one row joined with every row from aliased table). And the test check if the whoshee can work with aliased table.
Ergo, I think the code should be left intact and the warning should be silenced:
https://stackoverflow.com/questions/5225780/turn-off-a-warning-in-sqlalchemy