add: finish forge stuff

crates/core/src/model/communities.rs

@@ -258,6 +258,8 @@ pub struct Post {
     pub poll_id: usize,
     /// The title of the post (in communities where titles are enabled).
     pub title: String,
+    /// If the post is "open". Posts can act as tickets in a forge community.
+    pub is_open: bool,
 }
 
 impl Post {
@@ -284,6 +286,7 @@ impl Post {
             is_deleted: false,
             poll_id,
             title: String::new(),
+            is_open: true,
         }
     }