chore(docs): starting a migration notes section

docs/docs/misc/migration_notes.md

@@ -0,0 +1,41 @@
+---
+title: Migration notes
+description: Read about migration notes from previous versions, which could solve problems while updating
+keywords: [sandbox, cli, aztec, notes, migration, updating, upgrading]
+---
+
+Aztec is in full-speed development. Literally every version breaks compatibility with the previous ones. This page attempts to target errors and difficulties you might encounter when upgrading, and how to resolve them.
+
+## ≥0.17
+
+### Importing contracts in JS
+
+Contracts are now imported from a file with the type's name.
+
+For example:
+
+```js
+import { TokenContract } from '@aztec/noir-contracts/Token'
+```
+
+instead of
+
+```js
+import { TokenContract } from '@aztec/noir-contracts/types'
+```
+
+### Importing contracts in Nargo.toml
+
+Aztec contracts are now moved outside of the `src` folder, so you need to update your imports.
+
+For example, for `easy_private_token_contract`, you'd import them like this:
+
+```rust
+easy_private_token_contract = {tag ="v0.1.0-alpha62", git = "<https://github.com/AztecProtocol/aztec-packages>", directory = "yarn-project/noir-contracts/src/contracts/easy_private_token_contract"}
+```
+
+Now, just remove the `src` folder, as such:
+
+```rust
+easy_private_token_contract = {tag ="v0.1.0-alpha62", git = "<https://github.com/AztecProtocol/aztec-packages>", directory = "yarn-project/noir-contracts/src/contracts/easy_private_token_contract"}
+```