Added script for creating Magento admin

compose/bin/admin-user-create

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+USERNAME="admin"
+EMAIL="admin@example.com"
+FIRSTNAME="Admin"
+LASTNAME="Admin"
+PASSWORD="Admin123"
+
+bin/magento admin:user:create \
+    --admin-user=${USERNAME} \
+    --admin-password=${PASSWORD} \
+    --admin-email=${EMAIL} \
+    --admin-firstname=${FIRSTNAME} \
+    --admin-lastname=${LASTNAME}
+
+if [ $? -eq 0 ]; then
+    echo "Username: ${USERNAME}"
+    echo "Email: ${EMAIL}"
+    echo "Firstname: ${FIRSTNAME}"
+    echo "Lastname: ${LASTNAME}"
+    echo "Password: ${PASSWORD}"
+else
+    echo "Error creating admin user."
+fi