Can't show data with postgres + php - php

Question

i'm trying to make a web app with php and postgres but i have problems showing the data.
This is my view, it's just a simple login.
<form method="post" action="../Controlador/logueo.php" role="form" class="form-inline">
<div class="form-group">
<input name="nombre" type="text" class="form-control" placeholder="Introduce tu usuario">
</div>
<br>
<div class="form-group">
<br>
<input name="contraseña" type="password" class="form-control"
placeholder="Contraseña">
</div>
<br>
<br>
<button type="submit" class="btn btn-primary">Enviar</button>
</form>
This is ../Controlador/logueo.php and here is where i have problems. I can't show the info in $alumno (the variable in foreach), i tried to make an echo and nothing happens...
<?php
include("../Modelo/alumno.php");
$al = new alumno();
$alumnos = $al->obtenerAlumnos();
echo $alumnos;
foreach ($alumnos as $alumno) {
echo $alumno[0];
if ($alumno[0] == $_POST[nombre] && $alumno[5] == $_POST[contraseña] ){
//Do something
}
}
?>
And this is Modelo/alumno.php
<?php
class alumno
{
function _construct()
{
}
function obtenerAlumnos()
{
include("conexion.php");
$query = "SELECT * FROM alumno";
$result = pg_query($squery);
$alumnos = array();
while ($row = pg_fetch_row($result)) {
array_push($alumnos, $row);
}
return $alumnos;
}
}
?>
finally i have Conexion.php
<?php
$db = pg_connect("host=localhost port=5432 dbname=Tarea3BD user=postgres password=motorola13")
or die('Could not connect: ' . pg_last_error());
?>
Hope someone can help me, i'm new with php and postgres.
Many thanks.