Centralize auth messages (#269)

* Add i18n-tasks

* Add auth-related i18n

* Centralize auth messages

* Remove safe navigation

* Revert "Remove safe navigation"

This reverts commit 56b5e01e5e.

* Remove newline in Gemfile

config/i18n-tasks.yml

@@ -0,0 +1,25 @@
+base_locale: en
+data:
+  read:
+    - config/locales/%{locale}.yml
+  write:
+    - config/locales/%{locale}.yml
+  router: conservative_router
+search:
+  paths:
+    - app/
+  relative_roots:
+    - app/controllers
+    - app/helpers
+    - app/mailers
+    - app/presenters
+    - app/views
+  strict: true
+  ## Files or `File.fnmatch` patterns to exclude from search. Some files are always excluded regardless of this setting:
+  ##   *.jpg *.jpeg *.png *.gif *.svg *.ico *.eot *.otf *.ttf *.woff *.woff2 *.pdf *.css *.sass *.scss *.less
+  ##   *.yml *.json *.zip *.tar.gz *.swf *.flv *.mp3 *.wav *.flac *.webm *.mp4 *.ogg *.opus *.webp *.map *.xlsx
+  exclude:
+    - app/assets/images
+    - app/assets/fonts
+    - app/assets/videos
+    - app/assets/builds