add reactions support to thread

app/models.py

@@ -256,3 +256,28 @@ class APIRateLimits(Model):
                 return True
         else:
             return False
+
+class Reactions(Model):
+    table = "reactions"
+
+    @classmethod
+    def for_post(cls, post_id):
+        qb = db.QueryBuilder(cls.table)\
+            .select("reaction_text, COUNT(*) as c")\
+            .where({"post_id": post_id})\
+            .group_by("reaction_text")\
+            .order_by("c", False)
+        result = qb.all()
+        return result if result else []
+
+    @classmethod
+    def get_users(cls, post_id, reaction_text):
+        q = """
+            SELECT user_id, username FROM reactions
+            JOIN
+                users ON users.id = user_id
+            WHERE
+                post_id = ? AND reaction_text = ?
+        """
+
+        return db.query(q, post_id, reaction_text)