Update README.md

Author: jaenixlee

README.md

@@ -114,6 +114,9 @@ Docketeer is an open source initiative comprising contributions from dozens of t
 The local configuration for Docketeer was setup to be as simple as possible for the end-user. <br />
 Follow the steps below to get started with Docketeer.
 
+## Prerequisites:
+You must have Docker Desktop installed!
+
 #### STEP 1 — Clone the repository
 
 ```sh