Support elliptic curve SSH keys for deployment

Gemfile

@@ -74,6 +74,10 @@ group :development do
   gem "capistrano-rails", "~> 1.4", require: false
   gem "capistrano-rbenv", require: false
   gem 'capistrano3-puma', require: false
+
+  # Necessary for elliptic curve SSH keys
+  gem 'rbnacl', ">= 3.2", "<5.0"
+  gem 'bcrypt_pbkdf', ">= 1.0", "<2.0"
 end
 
 group :test do

Gemfile.lock

@@ -54,6 +54,7 @@ GEM
     arel (9.0.0)
     ast (2.4.0)
     bcrypt (3.1.12)
+    bcrypt_pbkdf (1.0.0)
     bindex (0.5.0)
     binding_of_caller (0.8.0)
       debug_inspector (>= 0.0.1)
@@ -233,6 +234,8 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
+    rbnacl (4.0.2)
+      ffi
     responders (2.4.0)
       actionpack (>= 4.2.0, < 5.3)
       railties (>= 4.2.0, < 5.3)
@@ -320,6 +323,7 @@ PLATFORMS
 DEPENDENCIES
   annotate
   bcrypt (~> 3.1.7)
+  bcrypt_pbkdf (>= 1.0, < 2.0)
   binding_of_caller
   bootsnap (>= 1.1.0)
   capistrano (~> 3.10)
@@ -348,6 +352,7 @@ DEPENDENCIES
   pundit (~> 1.1)
   rails (~> 5.2.0)
   rails-i18n (~> 5.1)
+  rbnacl (>= 3.2, < 5.0)
   rubocop (~> 0.56.0)
   sass-rails (~> 5.0)
   selenium-webdriver