Add database seeder for demo data

Created ForumSeeder to generate sample communities, posts, comments, and votes.
Useful for testing and demonstrating the forum functionality.

database/seeders/ForumSeeder.php

@@ -0,0 +1,93 @@
+<?php
+
+namespace Database\Seeders;
+
+use App\Models\Comment;
+use App\Models\Community;
+use App\Models\Post;
+use App\Models\User;
+use App\Models\Vote;
+use Illuminate\Database\Seeder;
+
+class ForumSeeder extends Seeder
+{
+    public function run(): void
+    {
+        $users = User::factory(10)->create();
+
+        $communities = [];
+        $communityNames = ['Programming', 'Gaming', 'Music', 'Movies', 'Technology'];
+
+        foreach ($communityNames as $name) {
+            $communities[] = Community::create([
+                'name' => $name,
+                'description' => "A community for {$name} enthusiasts",
+                'created_by' => $users->random()->id,
+            ]);
+        }
+
+        foreach ($users as $user) {
+            $user->subscribedCommunities()->attach(
+                collect($communities)->random(rand(1, 3))->pluck('id')
+            );
+        }
+
+        foreach ($communities as $community) {
+            $posts = [];
+            for ($i = 0; $i < rand(5, 15); $i++) {
+                $posts[] = Post::create([
+                    'community_id' => $community->id,
+                    'user_id' => $users->random()->id,
+                    'title' => fake()->sentence(),
+                    'content' => rand(0, 1) ? fake()->paragraphs(rand(1, 3), true) : null,
+                    'type' => 'text',
+                ]);
+            }
+
+            foreach ($posts as $post) {
+                for ($i = 0; $i < rand(0, 5); $i++) {
+                    $comment = Comment::create([
+                        'post_id' => $post->id,
+                        'user_id' => $users->random()->id,
+                        'content' => fake()->paragraph(),
+                    ]);
+
+                    if (rand(0, 1)) {
+                        Comment::create([
+                            'post_id' => $post->id,
+                            'user_id' => $users->random()->id,
+                            'parent_id' => $comment->id,
+                            'content' => fake()->paragraph(),
+                        ]);
+                    }
+                }
+
+                foreach ($users->random(rand(1, 8)) as $voter) {
+                    Vote::create([
+                        'user_id' => $voter->id,
+                        'voteable_id' => $post->id,
+                        'voteable_type' => Post::class,
+                        'vote' => rand(0, 1) ? 1 : -1,
+                    ]);
+                }
+            }
+        }
+
+        foreach (Post::all() as $post) {
+            $post->votes = $post->votes()->sum('vote');
+            $post->save();
+        }
+
+        foreach (Comment::all() as $comment) {
+            $comment->votes = $comment->votes()->sum('vote');
+            $comment->save();
+        }
+
+        foreach (User::all() as $user) {
+            $postKarma = $user->posts()->sum('votes');
+            $commentKarma = $user->comments()->sum('votes');
+            $user->karma = $postKarma + $commentKarma;
+            $user->save();
+        }
+    }
+}