docs(core): add new migration path for Lerna 5.1

docs/shared/migration/lerna-and-nx.md

@@ -23,7 +23,67 @@ Nx comes with a powerful task scheduler that intelligenty runs operations and ma
 - **Caching -** You get Nx's [computation caching](/using-nx/caching) for free. All operations, including artifacts and terminal output are restored from the cache (if present) in a completely transparent way without disrupting your DX. No configuration needed. Obviously this results in an incredible speed improvement.
 - **Distributed Task Execution -** This is unique to Nx. In combination with Nx Cloud your tasks are automatically distributed across CI agents, taking into account build order, maximizing parallelization and thus agent utilization. It even learns from previous runs to better distribute tasks! [Learn more](/using-nx/dte)
 
-## Add Nx to an existing Lerna monorepo
+## Integrating Nx with Lerna
+
+Since the [Nx core team now also maintains Lerna](https://blog.nrwl.io/lerna-is-dead-long-live-lerna-61259f97dbd9), there are a lot of different possibilities for integrating the two. The main strategy is to keep using Lerna's bootstrapping and publishing features, but use Nx for the fast task scheduling to speed up Lerna workspaces.
+
+There are two options:
+
+- Upgrade to the latest Lerna version and enable Nx by adding the `useNx` flag to your `lerna.json` file without changing anything else (including your current Lerna commands)
+- Directly using the Nx commands
+
+### Use Nx for task scheduling, without changing the Lerna setup
+
+Starting with Lerna 5.1 (currently in beta) you have Nx as an additional option to the existing `p-map` and `q-map` (previously used by Lerna) for running tasks. This is the **preferred approach if you have already a Lerna repository** since the impact is the lowest, while the benefit is still very high.
+
+To enable Nx support (and thus speed up task running) go through the following steps:
+
+**1. Install Nx**
+
+```bash
+npm i nx --save-dev
+```
+
+(or the yarn/pnpm alternatives).
+
+**2. Adjust your lerna.json**
+
+Change your `lerna.json` by adding the following flag.
+
+```json
+// lerna.json
+{
+  ...
+  "useNx": true
+}
+```
+
+By default `useNx` will be set to `false`, so you have to explicitly opt-in.
+
+**3. Create a nx.json (optional but recommended)**
+
+Nx works even without `nx.json` but to configure some more details such as the `cacheableOperations` of your monorepo in particular, create a `nx.json` at the root of the monorepo. Alternatively you can also just run `npx nx init` to have one generated. Specify the cacheable operations, usually something like `build`, `test`, `lint` etc, depending on your workspace setup:
+
+```json
+// nx.json
+{
+  "extends": "nx/presets/npm.json",
+  "tasksRunnerOptions": {
+    "default": {
+      "runner": "nx/tasks-runners/default",
+      "options": {
+        "cacheableOperations": ["build"]
+      }
+    }
+  }
+}
+```
+
+Having done these steps, you can now keep using your Lerna repository as you did before. All the commands will work in a backwards compatible way but will be a lot faster. [Read our blog post for some benchmarks](https://blog.nrwl.io/lerna-used-to-walk-now-it-can-fly-eab7a0fe7700?source=friends_link&sk=6c827ec7c9adfc1c760ff2e3f3e05cc7).
+
+> Note, this does not include distributed caching or distributed task execution powered by Nx Cloud. But you can easily add support for it if wanted. All that's required is `npx nx connect-to-nx-cloud`.
+
+### Switch to the Nx native commands in your Lerna workspace
 
 Nx can be added to an existing Lerna monorepo by running the following command: