diff --git a/BUGS.md b/BUGS.md
index fe45c8d..be95626 100644
--- a/BUGS.md
+++ b/BUGS.md
@@ -1,6 +1,10 @@
 
 # BUGS
 
+- SQLAlchemy error (rollback em accao no final de um topico):
+    Users/mjsb/Library/Python/3.7/lib/python/site-packages/sqlalchemy/sql/crud.py:700: SAWarning: Column 'studenttopic.student_id' is marked as a member of the primary key for table 'studenttopic', but has no Python-side or server-side default generator indicated, nor does it indicate 'autoincrement=True' or 'nullable=True', and no explicit value is passed.  Primary key columns typically may not store NULL. Note that as of SQLAlchemy 1.1, 'autoincrement=True' must be indicated explicitly for composite (e.g. multicolumn) primary keys if AUTO_INCREMENT/SERIAL/IDENTITY behavior is expected for one of the columns in the primary key. CREATE TABLE statements are impacted by this change as well on most backends.
+  util.warn(msg)
+
 - quando a pergunta devolve comments, este é apresentado, mas fica persistente nas tentativas seguintes. devia ser limpo apos a segunda submissao.
 - a opcao max_tries na especificacao das perguntas é cumbersome... usar antes tries?
 - tabelas nas perguntas radio/checkbox não ocupam todo o espaço como em question.
diff --git a/learnapp.py b/learnapp.py
index 7c85c52..2a458cb 100644
--- a/learnapp.py
+++ b/learnapp.py
@@ -195,9 +195,11 @@ class LearnApp(object):
     # ------------------------------------------------------------------------
     # Start new topic
     # ------------------------------------------------------------------------
-    def start_topic(self, uid, topic):
+    async def start_topic(self, uid, topic):
+        loop = asyncio.get_running_loop()
         try:
-            self.online[uid]['state'].init_topic(topic)
+            await loop.run_in_executor(None, self.online[uid]['state'].init_topic, topic)
+            # self.online[uid]['state'].init_topic(topic)
         except KeyError as e:
             logger.warning(f'User "{uid}" tried to open nonexistent topic: "{topic}"')
             raise e
diff --git a/serve.py b/serve.py
index 28ac080..1b59ff5 100755
--- a/serve.py
+++ b/serve.py
@@ -146,11 +146,11 @@ class RootHandler(BaseHandler):
 # ----------------------------------------------------------------------------
 class TopicHandler(BaseHandler):
     @tornado.web.authenticated
-    def get(self, topic):
+    async def get(self, topic):
         uid = self.current_user
 
         try:
-            self.learn.start_topic(uid, topic)
+            await self.learn.start_topic(uid, topic)
         except KeyError:
             self.redirect('/')
         else:
--
libgit2 0.21.2