Add extra data field

db/migrations/1514397430_add_extra_data.down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE blocks
+    DROP COLUMN block_extra_data;

db/migrations/1514397430_add_extra_data.up.sql

@@ -0,0 +1,2 @@
+ALTER TABLE blocks
+    ADD COLUMN block_extra_data VARCHAR;

db/schema.sql

@@ -52,7 +52,8 @@ CREATE TABLE blocks (
     uncle_hash character varying(66),
     node_id integer NOT NULL,
     is_final boolean,
-    block_miner character varying(42)
+    block_miner character varying(42),
+    block_extra_data character varying
 );