add --configuration option

bin/account-manager.pl.in

@@ -28,6 +28,7 @@ my %options;
 GetOptions(
     \%options,
     'profile=s',
+    'configuration=s',
     'contacts=s',
     'delete',
     'displayname=s',
@@ -47,7 +48,9 @@ pod2usage(
     -verbose => 0
 ) unless $action;
 
-my $configuration = Config::Tiny->read('@sysconfdir@/manager.conf');
+my $configuration_file =
+    $options{configuration} || '@sysconfdir@/manager.conf';
+my $configuration = Config::Tiny->read($configuration_file);
 
 AccountManager::DB->register_db(
     driver   => $configuration->{database}->{type},