Add substreams integration template, readmes

substreams/ethereum-template/src/lib.rs

@@ -0,0 +1,13 @@
+
+use substreams_ethereum::pb::eth;
+
+use pb::tycho::evm::v1::{self as tycho};
+
+mod pb;
+
+#[substreams::handlers::map]
+fn map_changes(
+    block: eth::v2::Block,
+) -> Result<tycho::BlockContractChanges, substreams::errors::Error> {
+    todo!("Not implemented")
+}