[Migration fix] Renames script 83 to avoid dupliate naming. Fixes script 85 with existing column and too long constraint on utf8mb4.

application/migrations/083_create_station_logbook_relationship_table2.php

@@ -7,7 +7,7 @@ defined('BASEPATH') OR exit('No direct script access allowed');
 *   removing the need for lots of configuration files.
 */
 
-class Migration_create_station_logbook_relationship_table extends CI_Migration {
+class Migration_create_station_logbook_relationship_table2 extends CI_Migration {
 
     public function up()
     {

application/migrations/085_add_public_slug_to_stationlogbooks.php

@@ -15,16 +15,19 @@ class Migration_add_public_slug_to_stationlogbooks extends CI_Migration {
             $fields = array(
                 'public_slug' => array(
                     'type' => 'VARCHAR',
-                    'constraint' => '200',
+                    'constraint' => '191',
                     'null' => TRUE,
                     'unique' => TRUE
                 )
             );
 
+            if (!$this->db->field_exists('public_slug', 'station_logbooks')) {
                 $this->dbforge->add_column('station_logbooks', $fields);
 
                 $this->dbforge->add_key('public_slug');
             }
+            
+        }
     }
 
     public function down()