document migration format version 0.2.1

doc/migration-format.md

+# IndieHosters migration format, version 0.2.1
+
+When a user exports their data for domain.com, they get a zip or tar file that contains different files, depending on which application is
+running on their domain:
+
+## If using the 'static' application
+
+ TLS/domain.com.pem - Concatenation of the unencrypted private and public key of the TLS certificate, and intermediate CA cert if applicable.
+ static/www-content - static content to be placed in the web root
+
+## If using the 'static-git' application
+
+ TLS/domain.com.pem - Concatenation of the unencrypted private and public key of the TLS certificate, and intermediate CA cert if applicable.
+ static-git/GITURL - git url to pull the static website content from
+
+## If using the 'WordPress' application
+
+ TLS/domain.com.pem - Concatenation of the unencrypted private and public key of the TLS certificate, and intermediate CA cert if applicable.
+ mysql/dump.sql - the dump of all their MySQL databases
+ mysql/.env - contains the MySQL password
+ wordpress/.env - contains the MySQL password
+ wordpress/login.txt - username and password for the WordPress admin panel
+ wordpress/.htaccess - htaccess file for WordPress
+ wordpress/wp-content - php files to be placed in the web root