Added comments on classes to fix travis errors

htdocs/attributes/class/ProductAttribute.class.php

@@ -16,6 +16,10 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+/**
+ * Class ProductAttribute
+ * Used to represent a product attribute
+ */
 class ProductAttribute
 {
 	/**

htdocs/attributes/class/ProductAttributeValue.class.php

@@ -16,6 +16,10 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+/**
+ * Class ProductAttributeValue
+ * Used to represent a product attribute value
+ */
 class ProductAttributeValue
 {
 	/**

htdocs/attributes/class/ProductCombination.class.php

@@ -16,6 +16,10 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+/**
+ * Class ProductCombination
+ * Used to represent a product combination
+ */
 class ProductCombination
 {
 	/**

htdocs/attributes/class/ProductCombination2ValuePair.class.php

@@ -16,6 +16,10 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+/**
+ * Class ProductCombination2ValuePair
+ * Used to represent the relation between a product combination, a product attribute and a product attribute value
+ */
 class ProductCombination2ValuePair
 {
 	/**