create table tbl_categories

[dmtrs]

There must be a categories folder.
Each post must BELONG_TO one category.

[MrSoundless]

Looking at current blog engines, it would make more sense to have a MANY_MANY relation between post and category.

[dmtrs]

Will consider this but what role is the tags have then.
I imagine that an article belongs to one category...like a news paper ( or similar media ) the article could be under one page with a certain category.
The MANY_MANY comes to the tags, which is not categories, but have a similar meaning.

[MrSoundless]

Even in online newssites you can find one article in multiple categories. Tags are especially there for search etc.