Changed sequence of commands

Moved the command "bin/mysqldump", since this is only available for a new "docker-magento" user after downloading the Docker Compose template.

README.md

@@ -194,9 +194,6 @@ open https://magento.test
 #### Existing Projects
 
 ```bash
-# Take a backup of your existing database:
-bin/mysqldump > ~/Sites/existing/magento.sql
-
 # Create your project directory then go into it:
 mkdir -p ~/Sites/magento
 cd $_
@@ -204,6 +201,9 @@ cd $_
 # Download the Docker Compose template:
 curl -s https://raw.githubusercontent.com/markshust/docker-magento/master/lib/template | bash
 
+# Take a backup of your existing database:
+bin/mysqldump > ~/Sites/existing/magento.sql
+
 # Replace with existing source code of your existing Magento instance:
 cp -R ~/Sites/existing src
 # or: git clone git@github.com:myrepo.git src