message: Remove README's from text search field
  Ref
diff: @@ -53,9 +53,8 @@ pub fn update_search_index(conn: &Connection) -> Result<u64, Error> {
  setweight(to_tsvector(coalesce(releases.description, '')), 'B') ||
  setweight(to_tsvector(coalesce((
  SELECT string_agg(value, ' ')
  - FROM json_array_elements_text(releases.keywords)), '')), 'B') ||
  - setweight(to_tsvector(coalesce(releases.readme, '')), 'C') ||
  - setweight(to_tsvector(coalesce(releases.description_long, '')), 'C') as content
  + FROM json_array_elements_text(releases.keywords)), '')), 'B')
  + as content
  FROM releases
  INNER JOIN crates ON crates.id = releases.crate_id
  ORDER BY releases.crate_id, releases.release_time DESC
  