Fixes a few crashes and search functionality. (#307)

* Fixes a few crashes and search functionality.

* Use PostError

src/forum.nim

@@ -882,6 +882,11 @@ routes:
             where t.id = ? and isDeleted = 0 and category = c.id;"""
 
     let threadRow = getRow(db, threadsQuery, id)
+    if threadRow[0].len == 0:
+      let err = PostError(
+        message: "Specified thread does not exist"
+      )
+      resp Http404, $(%err), "application/json"
     let thread = selectThread(threadRow, selectThreadAuthor(id))
 
     let postsQuery =
@@ -927,9 +932,14 @@ routes:
 
   get "/specific_posts.json":
     createTFD()
-    var
+    var ids: JsonNode
+    try:
       ids = parseJson(@"ids")
-
+    except JsonParsingError:
+      let err = PostError(
+        message: "Invalid JSON in the `ids` parameter"
+      )
+      resp Http400, $(%err), "application/json"
     cond ids.kind == JArray
     let intIDs = ids.elems.map(x => x.getInt())
     let postsQuery = sql("""

src/fts.sql

@@ -7,6 +7,7 @@ SELECT
         post_id,
         post_content,
         cdate,
+        person.id,
         person.name AS author,
         person.email AS email,
         strftime('%s', person.lastOnline) AS lastOnline,