Make the database primary key incremental

[zhouhao]

For now, the service use https://github.com/Devskiller/friendly-id for primary id generation.
While the generated id is not incremental, which means the latter generated id may have smaller lexicographical order.

The issue is that if a page has multiple notes, there are displayed based on the id order, not the timestamp.
I feel it is better to use a better id generate mechanism to make sure the latter generated one have increased order, e.g. snowflake