Why isn't act-as-taggable-on adding tags to posts?

Just set everything in acts-as-taggable-on but now it's not adding tags to posts. Here's the post model

acts_as_taggable_on :tags

in th user model

acts_as_tagger

in the posts controller

def permit_post
params.require(:post).permit(:image, :title, :long, :anonymous, :facenumber, :hidden, :granted, :tag_list => []);
end

.

puts @tags
#=>ActsAsTaggableOn::Tag Load (0.3ms) SELECT "tags".* FROM "tags" INNER JOIN "taggings" ON "tags"."id" = "taggings"."tag_id" WHERE "taggings"."taggable_id" = ? AND "taggings"."taggable_type" = ? AND "taggings"."context" = ? [["taggable_id", 26], ["taggable_type", "Post"], ["context", "tags"]] (0.3ms) SELECT COUNT(*) FROM "tags" INNER JOIN "taggings" ON "tags"."id" = "taggings"."tag_id" WHERE "taggings"."taggable_id" = ? AND "taggings"."taggable_type" = ? AND "taggings"."context" = ? [["taggable_id", 26], ["taggable_type", "Post"], ["context", "tags"]]
puts @post.tag_list
#=> 'tag1, tag2,tags'