add migrations that fixes issues with clipboard tables, fixes #776

db/migrations/5.1.25_adjust_clipboard_tables.php

+<?php
+final class AdjustClipboardTables extends Migration
+{
+    public function description()
+    {
+        return 'Alter clipboard tables by fixing indices, column types and collations';
+    }
+
+    protected function up()
+    {
+        $query = "ALTER TABLE `clipboards`
+                  CHANGE COLUMN `name` `name` VARCHAR(256) NOT NULL DEFAULT '',
+                  ADD INDEX `user_id` (`user_id`)";
+        DBManager::get()->exec($query);
+
+        $query = "ALTER TABLE `clipboard_items`
+                  CHANGE COLUMN `range_id` `range_id` CHAR(32) CHARACTER SET latin1 COLLATE `latin1_bin` NOT NULL,
+                  ADD INDEX `clipboard_id` (`clipboard_id`),
+                  ADD INDEX `range` (`range_id`,`range_type`)";
+        DBManager::get()->exec($query);
+    }
+
+    protected function down()
+    {
+        $query = "ALTER TABLE `clipboard_items`
+                  CHANGE COLUMN `range_id` `range_id` VARCHAR(98) CHARACTER SET latin1 COLLATE `latin1_bin` NOT NULL,
+                  DROP INDEX `clipboard_id`,
+                  DROP INDEX `range`";
+        DBManager::get()->exec($query);
+
+        $query = "ALTER TABLE `clipboards`
+                  CHANGE COLUMN `name` `name` VARCHAR(256) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL DEFAULT '',
+                  DROP INDEX `user_id`";
+        DBManager::get()->exec($query);
+    }
+}