get rank for user doesn't work with postgresql

[MoJafer]

Welcome

i just want to get a rank for current user
I'am did current_user.rank _for(:total_points)

then I get this error when i use postgresql while its work whitout any issue on sqlite3

PG::WrongObjectType: ERROR: count(*) must be used to call a parameterless aggregate function
LINE 1: SELECT COUNT() FROM "users" LEFT JOIN rs_reputations ON user...
^
: SELECT COUNT() FROM "users" LEFT JOIN rs_reputations ON users.id = rs_reputations.target_id AND rs_reputations.target_type = 'User' AND rs_reputations.reputation_name = 'total_points' AND rs_reputations.active = 't' WHERE (rs_reputations.value > 0.0)