Merge pull request #114 from hpi-swa-teaching/103-metacello-installation

Add metacello installation instruction to readme

README.md

@@ -14,5 +14,22 @@ In order to use our tool, you have to install it in your Squeak image. Our prefe
 - For later updates, you can just pull the new version from the Git Repository. To do that, select the `dev` branch and click the button <kbd>Pull</kbd>.
 - Once the new version was downloaded, right click the latest commit and choose <kbd>Checkout objects</kbd>.
 
+### Metacello
+- Open a workspace and execute
+```smalltalk
+Metacello new
+    baseline: 'ChangesReloaded';
+    repository: 'github://hpi-swa-teaching/ChangesBrowser:dev/packages';
+    load
+```
+as well as
+```smalltalk
+Metacello new
+    baseline: 'Changes';
+    repository: 'github://hpi-swa-teaching/ChangesBrowser:dev/packages';
+    load
+```
+- This is necessary because the 2020 project supports the 2017 project, but the browsers themselves have their own baselines. You need both for full functionality.
+
 ### Usage
 After you installed the tool you have to execute `CRBrowser open` in a Workspace in order to work with it. Alternatively, you can open it from the `CHBrowser` with the button <kbd>Switch to simple view</kbd>.