Include backwards compatibility link in README

Author: axic

README.md

@@ -25,6 +25,7 @@ eWASM:
 * specifies an [Ethereum environment interface](./eth_interface.md) to facilitate interaction with the Ethereum environment from an *eWASM contract*
 * specifies [metering](./metering.md) for instructions
 * and aims to restrict [non-deterministic behavior](https://github.com/WebAssembly/design/blob/master/Nondeterminism.md)
+* specifies a backwards compatible upgrade path to EVM1
 
 ### Goals of the eWASM project
 
@@ -50,6 +51,7 @@ eWASM:
 * [Rationale](./rationale.md)
 * [Ethereum environment interface](./eth_interface.md)
 * [eWASM Contract Interface](./contract_interface.md)
+* [Backwards compatibility instructions](./backwardsCompatibility.md)
 * [Original Proposal](https://github.com/ethereum/EIPs/issues/48) (EIP#48)
 * [WebAssembly design documents](https://github.com/WebAssembly/design)