1 files changed, 26 insertions, 0 deletions
diff --git a/internal/db/migrations/blog/00004_tags.sql b/internal/db/migrations/blog/00004_tags.sql
new file mode 100644
index 0000000..a2ac86a
--- /dev/null
+++ b/internal/db/migrations/blog/00004_tags.sql
@@ -0,0 +1,26 @@
+-- +goose Up
+-- Tags are shared by posts. The slug is both the URL (/tag/<slug>) and the
+-- dedupe key, so "Go" and "go" are one tag (the first spelling is kept).
+CREATE TABLE tags (
+    id    bigserial PRIMARY KEY,
+    name  text NOT NULL,
+    slug  text NOT NULL UNIQUE
+);
+CREATE TABLE post_tags (
+    post_id  bigint NOT NULL REFERENCES posts(id) ON DELETE CASCADE,
+    tag_id   bigint NOT NULL REFERENCES tags(id) ON DELETE CASCADE,
+    PRIMARY KEY (post_id, tag_id)
+);
+CREATE INDEX post_tags_tag ON post_tags (tag_id);
+
+-- Two more layout modules: the tag list and the tag cloud.
+ALTER TABLE modules DROP CONSTRAINT modules_kind_check;
+ALTER TABLE modules ADD CONSTRAINT modules_kind_check
+    CHECK (kind IN ('title', 'logo', 'menu', 'archive', 'recent', 'html', 'rss', 'text', 'sitemap', 'tags', 'tagcloud'));
+
+-- +goose Down
+DELETE FROM modules WHERE kind IN ('tags', 'tagcloud');
+ALTER TABLE modules DROP CONSTRAINT modules_kind_check;
+ALTER TABLE modules ADD CONSTRAINT modules_kind_check
+    CHECK (kind IN ('title', 'logo', 'menu', 'archive', 'recent', 'html', 'rss', 'text', 'sitemap'));
+DROP TABLE post_tags, tags;