Release v0.5.5

Breaking change
Changed tables name
The old version database can be fixed by these DDL/DML

ALTER TABLE tag RENAME TO tags;
ALTER TABLE tag_usage RENAME TO tags_usage;
ALTER TABLE post RENAME TO posts;

ALTER TABLE settings DROP COLUMN domain;
ALTER TABLE settings DROP COLUMN copyright;
ALTER TABLE settings DROP COLUMN license;

ALTER TABLE settings RENAME COLUMN name TO item;
ALTER TABLE settings RENAME COLUMN admin_password TO content;

UPDATE settings SET item='admin_password' WHERE id=1;

Others:

1. Added access log (printed in console)
2. TLS supported, thanks to flyingblackshark
3. etc.