Update tags index to handle issue # 9

Now checks for the file and either copies a backup or creates a blank
file.

blog/by_tag/index.php

@@ -32,8 +32,7 @@
     //}
     //echo "</ul>\n";
   //}
-  
-  # Tags rewrite
+  function read_tags($tags_file){
     $tags_csv = array_map('str_getcsv', file('tags.csv'));
     $tags_rows = sizeof($tags_csv);
     $tags_coloums = sizeof($tags_csv[0]);
@@ -64,5 +63,20 @@
       $coloum_number++;
     }
     echo "</ul>\n";
+  }
+  
+  
+  # Tags rewrite
+  if (file_exists('tags.csv')){
+    read_tags('tags.csv');
+  } elseif( file_exists('tags.csv.bak') ){
+    if (copy('tags.csv.bak', './tags.csv')) {
+      read_tags('tags.csv');
+    }
+  }else {
+    $empty_csv = fopen("tags.csv", "w") or die("Cannot write new tags.csv file.");
+    fwrite($empty_csv, "");
+    fclose($empty_csv);
+  }
   include_once ($_SERVER['DOCUMENT_ROOT'].'/common/php/footer.php');
 ?>