Merge pull request civicrm#17741 from eileenmcnaughton/eventcart

Add eventcart shell

.gitignore

@@ -4,6 +4,7 @@
 /ext/*
 !/ext/sequentialcreditnotes
 !/ext/flexmailer
+!/ext/eventcart
 backdrop/
 bower_components
 CRM/Case/xml/configuration

ext/eventcart/README.md

@@ -0,0 +1,44 @@
+# eventcart
+
+![Screenshot](/images/screenshot.png)
+
+(*FIXME: In one or two paragraphs, describe what the extension does and why one would download it. *)
+
+The extension is licensed under [AGPL-3.0](LICENSE.txt).
+
+## Requirements
+
+* PHP v7.0+
+* CiviCRM (*FIXME: Version number*)
+
+## Installation (Web UI)
+
+This extension has not yet been published for installation via the web UI.
+
+## Installation (CLI, Zip)
+
+Sysadmins and developers may download the `.zip` file for this extension and
+install it with the command-line tool [cv](https://github.com/civicrm/cv).
+
+```bash
+cd <extension-dir>
+cv dl eventcart@https://github.com/FIXME/eventcart/archive/master.zip
+```
+
+## Installation (CLI, Git)
+
+Sysadmins and developers may clone the [Git](https://en.wikipedia.org/wiki/Git) repo for this extension and
+install it with the command-line tool [cv](https://github.com/civicrm/cv).
+
+```bash
+git clone https://github.com/FIXME/eventcart.git
+cv en eventcart
+```
+
+## Usage
+
+(* FIXME: Where would a new user navigate to get started? What changes would they see? *)
+
+## Known Issues
+
+(* FIXME *)