Add index on block_number column (#43)

migrations/1509484288_add_block_index.down.sql

@@ -0,0 +1 @@
+DROP INDEX block_number_index;

migrations/1509484288_add_block_index.up.sql

@@ -0,0 +1 @@
+CREATE INDEX block_number_index ON blocks (block_number);

migrations/schema.sql

@@ -149,6 +149,13 @@ ALTER TABLE ONLY transactions
     ADD CONSTRAINT transactions_pkey PRIMARY KEY (id);
 
 
+--
+-- Name: block_number_index; Type: INDEX; Schema: public; Owner: -
+--
+
+CREATE INDEX block_number_index ON blocks USING btree (block_number);
+
+
 --
 -- Name: transactions fk_test; Type: FK CONSTRAINT; Schema: public; Owner: -
 --