Unset modifiers of attributes that aren't abilities

app/imports/api/creature/creatureComputation.js

@@ -119,6 +119,8 @@ function writeAttributes(char) {
     }
     if (typeof att.mod === 'number'){
       op.updateMany.update.$set.mod = att.mod;
+    } else {
+      op.updateMany.update.$unset = {mod: 1};
     }
     return op;
   });

app/imports/api/creature/properties/Attributes.js

@@ -50,10 +50,12 @@ attributeSchema = schema({
 		type: Number,
 		optional: true,
 	},
+	// The computed value of the attribute
   value: {
     type: Number,
 		defaultValue: 0,
   },
+	// The computed modifier, provided the attribute is an ability
 	mod: {
 		type: SimpleSchema.Integer,
 		optional: true,