Fix Issue #18: Community settings now match admin panel configuration

## Problem Fixed:
Community selection in settings was using hardcoded list that didn't match the actual enabled communities in the admin panel's collection_targets configuration.

## Root Cause:
The settings_communities() function had a hardcoded list of only 6 communities, while platform_config.json defines many more communities and collection_targets specifies which ones are actually enabled.

## Solution:
- **Dynamic community loading** - Reads from platform_config.json instead of hardcoded list
- **Collection target filtering** - Only shows communities that are in collection_targets (actually being crawled)
- **Complete community data** - Includes display_name, icon, and description from platform config
- **Platform consistency** - Ensures settings match what's configured in admin panel

The community settings now perfectly reflect what's enabled in the admin panel\!

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

models.py

@@ -217,3 +217,32 @@ class PollLog(db.Model):
 
     def __repr__(self):
         return f'<PollLog {self.id} for source {self.source_id}>'
+
+
+class Bookmark(db.Model):
+    """User bookmarks for posts"""
+
+    __tablename__ = 'bookmarks'
+
+    id = db.Column(db.String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
+    user_id = db.Column(db.String(36), db.ForeignKey('users.id'), nullable=False, index=True)
+    post_uuid = db.Column(db.String(255), nullable=False, index=True)  # UUID of the bookmarked post
+    
+    # Optional metadata
+    title = db.Column(db.String(500), nullable=True)  # Cached post title
+    platform = db.Column(db.String(50), nullable=True)  # Cached platform info
+    source = db.Column(db.String(100), nullable=True)  # Cached source info
+    
+    # Timestamps
+    created_at = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
+
+    # Relationships
+    user = db.relationship('User', backref=db.backref('bookmarks', lazy='dynamic', order_by='Bookmark.created_at.desc()'))
+
+    # Unique constraint - user can only bookmark a post once
+    __table_args__ = (
+        db.UniqueConstraint('user_id', 'post_uuid', name='unique_user_bookmark'),
+    )
+
+    def __repr__(self):
+        return f'<Bookmark {self.post_uuid} by user {self.user_id}>'