Issue #11: Fix command line arguments reading

Signed-off-by: Lucas Fernandes de Oliveira <lfoliveira@inf.ufpr.br>

manager.sh

@@ -2,7 +2,7 @@
 
 # Script used as interface to manage a PostgreSQL database
 
-if [[ $# -ne 1 && $# -ne 2 ]]; then
+if [[ $# -ne 2 && $# -ne 3 ]]; then
     echo "Correct use: $0 <dbms> <task> [directory]"
     echo "The allowed dbms's are: psql and monet"
     echo "The allowed tasks are: create, load, fixture, drop and clean"