Merge pull request #351 from stellar/v0.12.0-changelog

Update changelog for v0.12.0

services/horizon/CHANGELOG.md

@@ -6,22 +6,43 @@ file.  This project adheres to [Semantic Versioning](http://semver.org/).
 As this project is pre 1.0, breaking changes may happen for minor version
 bumps.  A breaking change will get clearly notified in this log.
 
-## [Unreleased]
+## [v0.12.0] - 2017-03-08
+
+Big release this time for horizon:  We've made a number of breaking changes since v0.11.0 and have revised both our database schema as well as our data ingestion system.  We recommend that you take a backup of your horizon database prior to upgrading, just in case.  
+
+### Upgrade Notes
+
+Since this release changes both the schema and the data ingestion system, we recommend the following upgrade path to minimize downtime:
+
+1. Upgrade horizon binaries, but do not restart the service
+2. Run `horizon db migrate up` to migrate the db schema
+3. Run `horizon db reingest` in a background session to begin the data reingestion process
+4. Restart horizon
 
 ### Added
 
-- Operation and payment resources were changed to add a `transaction_hash` property.
+- Operation and payment resources were changed to add `transaction_hash` and `created_at` properties.
 - The ledger resource was changed to add a `header_xdr` property.  Existing horizon installations should re-ingest all ledgers to populate the history database tables with the data.  In future versions of horizon we will disallow null values in this column.  Going forward, this change reduces the coupling of horizon to stellar-core, ensuring that horizon can re-import history even when the data is no longer stored within stellar-core's database.
 - All Assets endpoint (`/assets`) that returns a list of all the assets in the system along with some stats per asset. The filters allow you to narrow down to any specific asset of interest.
 - Trade Aggregations endpoint (`/trade_aggregations`) allow for efficient gathering of historical trade data. This is done by dividing a given time range into segments and aggregate statistics, for a given asset pair (`base`, `counter`) over each of these segments.
 
+### Bug fixes
+
+- Ingestion performance and stability has been improved. 
+- Changes to an account's inflation destination no longer produce erroneous "signer_updated" effects. (https://github.com/stellar/horizon/issues/390)
+
 
 ### Changed
 
 - BREAKING CHANGE: The `base_fee` property of the ledger resource has been renamed to `base_fee_in_stroops` 
 - BREAKING CHANGE: The `base_reserve` property of the ledger resource has been renamed to `base_reserve_in_stroops` and is now expressed in stroops (rather than lumens) and as a JSON number. 
 - BREAKING CHANGE: The "Orderbook Trades" (`/orderbook/trades`) endpoint has been removed and replaced by the "All Trades" (`/trades`) endpoint.
 - BREAKING CHANGE: The Trade resource has been modified to generalize assets as (`base`, `counter`) pairs, rather than the previous (`sold`,`bought`) pairs.  
+- Full reingestion (i.e. running `horizon db reingest`) now runs in reverse chronological order.  
+
+### Removed
+
+- BREAKING CHANGE: Friendbot has been extracted to an external microservice.
 
 
 ## [v0.11.0] - 2017-08-15