GIN index uses to find posts by tag

-remove hive_post_tags table -extend hive_posts for a column with an arrays of tags id -tags are added next after a post, not in paralles as it was previously -fix bug with not removing tags for a post whose author removed tags during edition

tests/tests_api

-Subproject commit 0f0fd1af6d7e367849a87443c0137702b135e297
+Subproject commit eb454fc8250a988c1c5a4440a3d138b8f3941232