feat(doc): add migration section

README.md

@@ -195,3 +195,93 @@ To run all examples and play around with the code you have to run two separate c
 
 - `yarn dev` - runs webpack and node dev server
 - `yarn build:dev` - runs rollup in watch mode - livereload if you do changes to the insights library
+
+## Migrating from v0 to v1
+
+### `init` method signature has changed
+- `applicationID` is now called `appId`, to stay consistent with our [other js libraries](https://www.algolia.com/doc/guides/building-search-ui/upgrade-guides/js/?language=javascript#previous-usage).
+
+**Before**:
+```js
+  aa('init', {
+    applicationID: 'APPLICATION_ID',
+    apiKey: 'SEARCH_API_KEY'
+    // other props
+  })
+```
+
+**After**:
+```js
+  aa('init', {
+    appId: 'APPLICATION_ID',
+    apiKey: 'SEARCH_API_KEY'
+    // other props
+  })
+```
+
+### `initSearch` method has been removed
+This method was previously used to pass `getQueryID` helper. Now you need to explicitly call this helper
+and pass the result to methods that require it (namely `clickedObjectIDsAfterSearch` and `convertedObjectIDsAfterSearch`)
+``
+
+**Before**:
+```js
+ aa('initSearch', {
+    getQueryID: () => search.helper.lastResults.queryID
+ })
+```
+
+**After**:
+```js
+  const getQueryID = () => search.helper.lastResults.queryID
+```
+
+### `click` and `convert` methods have been renamed and their signatures have changed to reflect the different use cases covered by the insights client
+
+To make it clear that they are intended to be called in the context of a search:
+- `click` is now `clickedObjectIDsAfterSearch`
+- `convert` is now `convertedObjectIDsAfterSearch`
+
+The signatures have also changed:
+
+* On `clickedObjectIDsAfterSearch `
+  - `eventName: string` is now required
+  - `index: string` is now required
+  - `objectID: number | string` is now `objectIDs : Array<number | string>`
+  - `queryID: string` is now required, use the `getQueryID` helper documented
+  - `position: number` is now `positions : Array<number>`
+
+* On `convertedObjectIDsAfterSearch`
+  - `eventName: string` is now required
+  - `index: string` is now required
+  - `objectID: number | string` is now `objectIDs : Array<number | string>`
+  - `queryID: string` is now required, use the `getQueryID` helper documented
+
+**Before**:
+```js
+aa("click", {
+  objectID: "object1",
+  position: 42
+});
+aa("convert", {
+  objectID: "object1",
+  position: 42
+});
+```
+
+**After**:
+```js
+aa("clickedObjectIDsAfterSearch", {
+  index: "INDEX_NAME",
+  eventName: "Clicked item",
+  queryID: getQueryID(),
+  objectIDs: ["object1"],
+  positions: [42]
+});
+aa("convertedObjectIDsAfterSearch", {
+  index: "INDEX_NAME",
+  eventName: "Clicked item",
+  queryID: getQueryID(),
+  objectIDs: ["object1"]
+});
+```