Post array with multiple same input names - php

Question

Im having a form that posts an array (invoice[]) of company and invoice items.
My form got some inputs with the same name and i want to push them into the array and post them to the database as one row for each item. How can i push the items in item[0], item[1]...etc, in the same array to store it properly in the database ?
This is the input group that is been repeated in my form:
<tr>
<td class="col-xs-0">
<input type="checkbox" name="selected[]" class="checkall">
</td>
<td class="col-xs-5">
<textarea type="text" name="invoice[description]" class="form-control" id="description" rows="1" value="{{invdtl_itemDescription}}"></textarea>
</td>
<td class="col-xs-1">
<input type="number" name="invoice[unit]" class="form-control" id="unit" maxlength="5" pattern="\d+(\.\d{2})?">
</td>
<td class="col-xs-1">
<input type="number" name="invoice[qty]" class="form-control" id="qty" maxlength="5" pattern="\d+(\.\d{2})?">
</td>
<td class="col-xs-1">
<input type="number" name="invoice[price]" class="form-control" id="price" maxlength="5" pattern="\d+(\.\d{2})?">
</td>
<td class="col-xs-1">
<input type="number" name="invoice[discount]" class="form-control" id="discount" maxlength="5" pattern="\d+(\.\d{2})?">
</td>
<td class="col-xs-1">
<input type="number" name="invoice[discountPrice]" class="form-control" id="discountPrice" maxlength="5" pattern="\d+(\.\d{2})?">
</td>
<td class="col-xs-1">
<input type="number" name="invoice[total]" class="form-control" id="total" maxlength="5" pattern="\d+(\.\d{2})?">
</td>
<td class="col-xs-1">
<input type="number" name="invoice[vat]" class="form-control" id="vat" value="23" maxlength="3" pattern="\d+(\.\d{2})?">
</td>
</tr>
The array is posted with $.ajax to the database in two tables (one for invoice_header and one for invoice_details. Invoice items (the one that is been repeated in the form) should be stored in the invoice_details each row at a time.
Form data:
invoice[client]: 1
invoice[type]: receipt
invoice[invoice]: 155
invoice[date]: 2014-07-07
invoice[shipmethod]: 1
===== Item #1 =====
invoice[description]: Test
invoice[unit]: 1
invoice[qty]: 1
invoice[price]: 1
invoice[discount]: 1
invoice[discountPrice]: 1
invoice[total]: 1
invoice[vat]: 23
===== Item #2 =====
invoice[description]: Test 2
invoice[unit]: 2
invoice[qty]: 2
invoice[price]: 2
invoice[discount]: 2
invoice[discountPrice]: 2
invoice[total]: 2
invoice[vat]: 23