Transaction log
Name: alert_transactio_log
id	        auto increment	pk
user_id	        int	        Who is making the changes
field_name	varchar	        Column name
table_name	varchar	        Table ie., getting affected
module_id	int	        Which module? Ex: User/ alert
operation_id	int	        Functionality Ex:  Add, edit delete
table_id	int	        Pk of the table getting affected (worst case to put the data back)
old_data	varchar
new_data	varchar
created_by	int
created_date	UNIX timestamp
notification_flag	int	Does modified notification has to be sent ? (0,1)