Huge improvements for docs (#58)

docs/content/doc/setup/backups.md

@@ -0,0 +1,34 @@
+---
+date: "2019-02-12:00:00+02:00"
+title: "What to backup"
+draft: false
+type: "doc"
+menu:
+  sidebar:
+    parent: "setup"
+---
+
+# What to backup
+
+Vikunja does not store any data outside of the database.
+So, all you need to backup are the contents of that database and maybe the config file.
+
+## MySQL
+
+To create a backup from mysql use the `mysqldump` command:
+
+{{< highlight bash >}}
+mysqldump -u <user> -p -h <db-host> <database> > vkunja-backup.sql
+{{< /highlight >}}
+
+You will be prompted for the password of the mysql user.
+
+To restore it, simply pipe it back into the `mysql` command:
+
+{{< highlight bash >}}
+mysql -u <user> -p -h <db-host> <database> < vkunja-backup.sql
+{{< /highlight >}}
+
+## SQLite
+
+To backup sqllite databases, it is enough to copy the database elsewhere.