update wasm migrate docs

WASM_MIGRATE.md

@@ -1,10 +1,29 @@
 ## Wasm Migration Guide from Terra Classic
 Terra Rebirth is now using wasm module of [wasmd](https://github.com/CosmWasm/wasmd) and it introduces minor compatibility issue with Terra Classic.
 
+### Store
+
+#### Permission
+A code uploader can specify the permission of code instantiation
+```go
+const (
+	// AccessTypeUnspecified placeholder for empty value
+	AccessTypeUnspecified AccessType = 0
+	// AccessTypeNobody forbidden
+	AccessTypeNobody AccessType = 1
+	// AccessTypeOnlyAddress restricted to an address
+	AccessTypeOnlyAddress AccessType = 2
+	// AccessTypeEverybody unrestricted
+	AccessTypeEverybody AccessType = 3
+)
+```
+
 ### Instantiate 
 
+#### Reply
 The contracts are using reply to check instantiated contract address, 
 should update the proto file to the following.
+
 ```protobuf
 // MsgInstantiateContractResponse return instantiation result data
 message MsgInstantiateContractResponse {
@@ -15,6 +34,13 @@ message MsgInstantiateContractResponse {
 }
 ```
 
-Event key for instantiated contract also should be changed
-from `instantiate`.`contract_address` to `instantiate`.`_contract_address`.
+Ex) https://github.com/terraswap/terraswap/pull/47
+
+#### Event
+Event key for instantiated contract also should be changed from `instantiate`.`contract_address` to `instantiate`.`_contract_address`.
+
+#### Label
+Now label is used to represent the contract info
 
+#### Burn Operation
+`CosmosMsg::Bank(BankMsg::Burn)` is enabled