Refactoring Tickets

- Tickets now independent from registration
- Implemented money gem
#419

app/assets/javascripts/osem-tickets.js

@@ -0,0 +1,25 @@
+function update_price($this){
+    var id = $this.data('id');
+
+    // Calculate price for row
+    var value = $this.val();
+    var price = $('#price_' + id).text();
+    $('#total_row_' + id).text(value * price);
+
+    // Calculate total price
+    var total = 0;
+    $('.total_row').each(function( index ) {
+        total += parseInt($(this).text());
+    });
+    $('#total_price').text(total);
+}
+
+$( document ).ready(function() {
+    $('.quantity').each(function() {
+        update_price($(this));
+    });
+
+    $('.quantity').change(function() {
+        update_price($(this));
+    });
+});