Add withdrawals (EIP-4895) (#7)

Support for validator withdrawal objects:
- new table `eth.withdrawal_cids`
- new column `withdrawals_root` in `eth.header_cids`

Reviewed-on: #7

db/migrations/00004_create_eth_header_cids_table.sql

@@ -15,6 +15,7 @@ CREATE TABLE IF NOT EXISTS eth.header_cids (
     timestamp             BIGINT NOT NULL,
     coinbase              VARCHAR(66) NOT NULL,
     canonical             BOOLEAN NOT NULL DEFAULT TRUE,
+    withdrawals_root      VARCHAR(66) NOT NULL,
     PRIMARY KEY (block_hash, block_number)
 );
 

db/migrations/00021_create_eth_withdrawal_cids_table.sql

@@ -0,0 +1,16 @@
+-- +goose Up
+CREATE TABLE IF NOT EXISTS eth.withdrawal_cids (
+    block_number    BIGINT NOT NULL,
+    header_id       VARCHAR(66) NOT NULL,
+    cid             TEXT NOT NULL,
+    index           INTEGER NOT NULL,
+    validator       INTEGER NOT NULL,
+    address         VARCHAR(66) NOT NULL,
+    amount          NUMERIC NOT NULL,
+    PRIMARY KEY (index, header_id, block_number)
+);
+
+SELECT create_hypertable('eth.withdrawal_cids', 'block_number', migrate_data => true, chunk_time_interval => 32768);
+
+-- +goose Down
+DROP TABLE eth.withdrawal_cids;