Added private.item_qualities table.

diff --git a/Constants.lua b/Constants.lua
index 3ccb188..413cc2b 100644
--- a/Constants.lua
+++ b/Constants.lua
@@ -24,6 +24,18 @@
 local private	= select(2, ...)

 -------------------------------------------------------------------------------
+-- Item qualities.
+-------------------------------------------------------------------------------
+private.item_qualities = {
+	["COMMON"]	= 1,
+	["UNCOMMON"]	= 2,
+	["RARE"]	= 3,
+	["EPIC"]	= 4,
+	["LEGENDARY"]	= 5,
+	["ARTIFACT"]	= 6,
+}
+
+-------------------------------------------------------------------------------
 -- Filter flags.
 -------------------------------------------------------------------------------
 private.filter_flags = {