message: Added instructions to update
diff: @@ -17,6 +17,35 @@ previous index format.*
  - Added IndexReader. By default, index is reloaded automatically upon new commits (@fulmicoton)
  - SIMD linear search within blocks (@fulmicoton)
  +## How to update ?
  +
  +tantivy 0.9 brought some API breaking change.
  +To update from tantivy 0.8, you will need to go through the following steps.
  +
  +- `schema::INT_INDEXED` and `schema::INT_STORED` should be replaced by `schema::INDEXED` and `schema::INT_STORED`.
  +- The index now does not hold the pool of searcher anymore. You are required to create an intermediary object called
  +`IndexReader` for this.
  +
  + ```rust
  + // create the reader. You typically need to create 1 reader for the entire
  + // lifetime of you program.
  + let reader = index.reader()?;
  +
  + // Acquire a searcher (previously `index.searcher()`) is now written:
  + let searcher = reader.searcher();
  +
  + // With the default setting of the reader, you are not required to
  + // call `index.load_searchers()` anymore.
  + //
  + // The IndexReader will pick up that change automatically, regardless
  + // of whether the update was done in a different process or not.
  + // If this behavior is not wanted, you can create your reader with
  + // the `ReloadPolicy::Manual`, and manually decide when to reload the index
  + // by calling `reader.reload()?`.
  +
  + ```
  +
  +
  Tantivy 0.8.2
  =====================
  Fixing build for x86_64 platforms. (#496)
  