Update REST API documentation [ci skip]

#660

doc/repp-doc.md

@@ -17,4 +17,5 @@ Main communication specification through Restful EPP (REPP):
 
 [Contact related functions](repp/v1/contact.md)  
 [Domain related functions](repp/v1/domain.md)  
+[Domain transfers](repp/v1/domain_transfers.md)  
 [Account related functions](repp/v1/account.md)

doc/repp/v1/domain_transfers.md

@@ -0,0 +1,48 @@
+# Domain transfers
+
+## POST /repp/v1/domain_transfers
+Transfers domains.
+
+#### Request
+```
+GET /repp/v1/domain_transfers
+Accept: application/json
+Content-Type: application/json
+Authorization: Basic dGVzdDp0ZXN0dGVzdA==
+
+{
+   "data":{
+      "domainTransfers":[
+         {
+            "domainName":"example.com",
+            "transferCode":"63e7"
+         },
+         {
+            "domainName":"example.org",
+            "transferCode":"15f9"
+         }
+      ]
+   }
+}
+```
+
+#### Response on success
+```
+HTTP/1.1 204
+```
+
+#### Response on failure
+```
+HTTP/1.1 400
+Content-Type: application/json
+{
+   "errors":[
+      {
+         "title":"example.com transfer code is wrong"
+      },
+      {
+         "title":"example.org does not exist"
+      }
+   ]
+}
+```