Merge pull request #87 from joostbaptist/master

Added average aggregate function to relevance scores (fixes #75)

src/SearchableTrait.php

@@ -184,7 +184,7 @@ protected function makeGroupBy(Builder $query)
      */
     protected function addSelectsToQuery(Builder $query, array $selects)
     {
-        $selects = new Expression(implode(' + ', $selects) . ' as relevance');
+        $selects = new Expression('avg(' . implode(' + ', $selects) . ') as relevance');
         $query->addSelect($selects);
     }