Database changes (#15)

* Implement database changes

* Split foreign keys into their own migration

* Use whereColumn

* Rename flag.time

* Rename forum.flagCount

* Rename forum.newFlagCount

extensions/flags/migrations/2018_06_27_101500_change_flags_rename_time_to_created_at.php

@@ -0,0 +1,14 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Flarum\Database\Migration;
+
+return Migration::renameColumn('flags', 'time', 'created_at');

extensions/flags/migrations/2018_06_27_101600_change_flags_add_foreign_keys.php

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+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Schema\Builder;
+
+return [
+    'up' => function (Builder $schema) {
+        // Delete rows with non-existent entities so that we will be able to create
+        // foreign keys without any issues.
+        $schema->getConnection()
+            ->table('flags')
+            ->whereNotExists(function ($query) {
+                $query->selectRaw(1)->from('posts')->whereColumn('id', 'post_id');
+            })
+            ->delete();
+
+        $schema->getConnection()
+            ->table('flags')
+            ->whereNotExists(function ($query) {
+                $query->selectRaw(1)->from('users')->whereColumn('id', 'user_id');
+            })
+            ->update(['user_id' => null]);
+
+        $schema->table('flags', function (Blueprint $table) {
+            $table->foreign('post_id')->references('id')->on('posts')->onDelete('cascade');
+            $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
+        });
+    },
+
+    'down' => function (Builder $schema) {
+        $schema->table('flags', function (Blueprint $table) {
+            $table->dropForeign(['post_id', 'user_id']);
+        });
+    }
+];

extensions/flags/migrations/2018_06_27_105100_change_users_rename_flags_read_time_to_read_flags_at.php

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+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Flarum\Database\Migration;
+
+return Migration::renameColumn('users', 'flags_read_time', 'read_flags_at');