Adding SFTP docs

docs/configuration/transport/sftp.md

@@ -0,0 +1,23 @@
+# SFTP transport configuration
+
+ ## JSON
+```
+"Sftp": {
+  "host"      : "ftp.domain.com",
+  "port"      : 22,
+  "login"     : "login",
+  "password"  : "password",
+  "folder"    : "/folder"
+},
+```
+ ## General 
+-
+ 
+ ## Options
+host (mandatory)    = sftp host without schema ("ftp://")
+port                = sftp port (default: 22)
+login (mandatory)   = sftp login (mandatory if not anonymous)
+password (mandatory)= sftp password (mandatory if not anonymous)
+folder              = the folder you want to put the backup in. If not set, the backup will be put in the ftp root
+
+