Models and associations

* Comments
    * [x] create model
    * [x] has one post
    * [x] has many commentmeta
* Options
    * [x] create model
* Posts
    * [x] create model
    * [x] has many postmeta
    * [x] has many term-taxonomies (through `term_relationships`)
    * [x] has one user (author)
    * [x] has many comments
* Postmeta
    * [x] create model
    * [x] has one post
* Terms
    * [x] create model
    * [x] has many taxonomies (through `wp_term_taxonomy`)
* Term taxonomies
    * [x] create model
    * [x] has one taxonomy
    * [x] has one term
    * [x] has many posts (through `term_relationships`)
    * [x] has many links (through `term_relationships`)
* Term relationships
    * [x] create model
    * [x] has one post
    * [x] has one term-taxonomy
* Users
    * [x] create model
    * [x] has many posts
    * [x] has many usermeta
* Usermeta
    * [x] create model
    * [x] has one user
* Links
    * [x] create model
    * [x] has many term relationships
    * [x] has many term taxonomies (through `term_relationships`)