Disable invite button after sending invite

Changelog.md

@@ -5,6 +5,7 @@
 ## Bug fixes
 * Don't focus comment form on 'show n more comments' [#4265](https://github.com/diaspora/diaspora/issues/4265)
 * Do not render mobile photo view for none-existing photos [#4194](https://github.com/diaspora/diaspora/issues/4194)
+* Disable invite button after sending invite [#4173](https://github.com/diaspora/diaspora/issues/4173)
 
 ## Features
 * Admin: add option to find users under 13 (COPPA) [#4252](https://github.com/diaspora/diaspora/pull/4252)

app/views/invitations/new.html.haml

@@ -31,4 +31,4 @@
         %br
 
         %p
-          = submit_tag t('.send_an_invitation')
+          = submit_tag t('.send_an_invitation'), :disable_with => t('.sending_invitation')

config/locales/diaspora/en.yml

@@ -381,6 +381,7 @@ en:
       to: "To"
       personal_message: "Personal message"
       send_an_invitation: "Send an invitation"
+      sending_invitation: "Sending invitation..."
       send_invitation: "Send invitation"
       paste_link: "Share this link with your friends to invite them to Diaspora*, or email them the link directly."
       codes_left: