notification dao added

app/app/dao/notification/notification.py

+from app.helpers.misc import with_psql
+
+@with_psql
+def create(cur, nid, appkey, devid, name, desc, action_type, action):
+    query = """
+    INSERT INTO
+        notifications
+    VALUES
+        (%s, %s, %s, %s, %s, %s, %s)
+    """
+    cur.execute(query, (nid, appkey, devid, name, desc, action_type, action))
+       
+    return (True,)
+
+@with_psql
+def delete(cur, appkey, nid):
+    query = """
+    DELETE FROM
+        notifications
+    WHERE
+        id = %s
+    AND
+        app_key = %s
+    """
+    cur.execute(query, (nid, appkey))
+        
+    return (True,)
+
+@with_psql
+def get(cur, appkey, nid):
+    query = """
+    SELECT * FROM
+        notifications
+    WHERE
+        id = %s
+    AND
+        app_key = %s
+    """
+    cur.execute(query, (nid, appkey))
+    app = cur.fetchone()
+
+    if app is None:
+        return (False, 'Notification with appkey {} and id {} does not exist'.format(appkey, nid))
+    else:
+        return (True, app)
+
+    
+@with_psql
+def get_list(cur, appkey):
+    query = """
+    SELECT * FROM
+        notifications
+    WHERE
+        app_key = %s
+    """
+    cur.execute(query, (appkey,))
+
+    return (True, cur.fetchall())
+
+
+@with_psql
+def get_count(cur):
+    query = """
+    SELECT COUNT(*) FROM
+        notifications
+    """
+    cur.execute(query, ())
+
+    return (True, cur.fetchone())