📝 Add introduction to Readme

Author: leolabs

README.md

@@ -1,2 +1,14 @@
-# alfred-gitmoji
-Search for gitmoji using Alfred and copy them to the clipboard easily
+# Gitmoji workflow for Alfred
+Search for [gitmoji](https://gitmoji.carloscuesta.me/) using
+[Alfred](https://www.alfredapp.com/) and copy them to the clipboard easily.
+
+## Installation
+You can download the latest version [here](https://github.com/leolabs/alfred-gitmoji/releases/latest).
+Just open it in Alfred to install this workflow. No further steps are required.
+
+## Updating the database
+This workflow ships with the current version of the gitmoji database, so you can
+use it offline, if needed. If you want to update the database, run `gm update`.
+
+## Used libraries
+This workflow uses [jq](https://stedolan.github.io/jq/) to process the database.