service object to write out config files

test/fixtures/accounts.yml

@@ -5,3 +5,15 @@ account1:
   password: <%= CryptSerializer.dump('1q2w3e4r5t6y7u') %>
   home_folder: client_one
   contact_email: ftp-user@mailinator.com
+
+account2:
+  username: client-two
+  password: <%= CryptSerializer.dump('azsxdcfvgbhnjmk,l.;/') %>
+  home_folder: client_two
+  contact_email: ftp-user@mailinator.com
+
+account3:
+  username: client-three
+  password: <%= CryptSerializer.dump('p0o9i8u7y6t5r4e3w2q1') %>
+  home_folder: client_three
+  contact_email: ftp-user@mailinator.com