Rename the unified post date field.

Use post_date throughout the new schema while retaining hunt_date only as the legacy migration source.

internal/store/migrate.go

@@ -50,22 +50,22 @@ CREATE TABLE IF NOT EXISTS posts (
   title TEXT NOT NULL DEFAULT '',
   body TEXT NOT NULL,
   city TEXT NOT NULL DEFAULT '',
-  hunt_date TEXT NOT NULL DEFAULT '',
+  post_date TEXT NOT NULL DEFAULT '',
   hidden INTEGER NOT NULL DEFAULT 0,
   created_at TEXT NOT NULL,
   updated_at TEXT NOT NULL,
   CHECK (
-    (parent_id IS NULL AND title <> '' AND hunt_date <> '')
+    (parent_id IS NULL AND title <> '' AND post_date <> '')
     OR
-    (parent_id IS NOT NULL AND title = '' AND city = '' AND hunt_date = '' AND hidden = 0)
+    (parent_id IS NOT NULL AND title = '' AND city = '' AND post_date = '' AND hidden = 0)
   )
 )`},
 		{"index post replies", `
 CREATE INDEX IF NOT EXISTS idx_posts_parent_created
   ON posts(parent_id, created_at, id)`},
 		{"index root posts", `
-CREATE INDEX IF NOT EXISTS idx_posts_root_hunt
-  ON posts(hunt_date, hidden)
+CREATE INDEX IF NOT EXISTS idx_posts_root_date
+  ON posts(post_date, hidden)
   WHERE parent_id IS NULL`},
 		{"create post votes", `
 CREATE TABLE IF NOT EXISTS post_votes (
@@ -76,7 +76,7 @@ CREATE TABLE IF NOT EXISTS post_votes (
 )`},
 		{"copy questions", `
 INSERT INTO posts (
-  id, parent_id, author_id, title, body, city, hunt_date, hidden, created_at, updated_at
+  id, parent_id, author_id, title, body, city, post_date, hidden, created_at, updated_at
 )
 SELECT
   id, NULL, author_id, title, body, city, hunt_date, hidden, created_at, created_at
@@ -84,7 +84,7 @@ FROM questions
 ON CONFLICT (id) DO NOTHING`},
 		{"copy answers", `
 INSERT INTO posts (
-  id, parent_id, author_id, title, body, city, hunt_date, hidden, created_at, updated_at
+  id, parent_id, author_id, title, body, city, post_date, hidden, created_at, updated_at
 )
 SELECT
   'answer:' || question_id, question_id, author_id, '', body, '', '', 0, created_at, updated_at