add release instructions for the uninstall tool

src/dotnet-core-uninstall/README.md

@@ -0,0 +1,49 @@
+# dotnet-core-uninstall
+
+This project is a standalone uninstaller for Windows and MacOS.  It exists partially to ensure that a) it's easy to uninstall the SDK and b) SDKs that are required by various VS versions aren't also uninstalled.
+
+# Releasing the tool
+
+To release the tool, you need to do the following:
+
+* bump the version of the tool in eng/Versions.props
+* send a PR with this change and get it merged
+* wait for the associated build pipeline in VSTS to complete
+* get the version generated from the build pipeline and use it to create a tag in git
+* use that tag to create a github release. Add release notes with
+  * A list of changes from the last release
+  * The install instructions, which are included below
+  * The 4 primary assets for the repo:
+    * Windows MSI from VSTS pipeline
+    * macOS tar.gz from VSTS pipeline
+    * Source code (zip) generated by GitHub at time of release creation
+    * Source code (tar.gz) generated by GitHub at time of release creation
+
+## Release notes template
+
+# Changes
+
+
+# Installation Instructions:
+
+## On Windows:
+
+1. Download the msi file below.
+2. Double click the msi file to install.
+3. Open a new command prompt.
+4. Check out the docs at https://aka.ms/dotnet-core-uninstall-docs
+5. Run the tool by using dotnet-core-uninstall.
+6. If you accidentally mess up your Visual Studio installation, use "Repair" in the Visual Studio installer.
+
+## On macOS:
+
+Download the tar.gz file below.
+Open terminal and change working directory to the directory with dotnet-core-uninstall.tar.gz.
+Use the following commands to install the tool and show help:
+
+```shell
+mkdir -p ~/dotnet-core-uninstall
+tar -zxf dotnet-core-uninstall.tar.gz -C ~/dotnet-core-uninstall
+cd ~/dotnet-core-uninstall
+./dotnet-core-uninstall -h
+```