Cache I18nContent translations

This way we avoid fetching each translation every time it's requested.
This reduces the amount of queries in the development logs and also
makes the test suite faster.

app/models/i18n_content.rb

@@ -94,4 +94,12 @@ class I18nContent < ApplicationRecord
       budgets.index.section_footer.description
     ]
   end
+
+  def self.translations_hash(locale)
+    Rails.cache.fetch(translation_class.where(locale: locale)) do
+      all.map do |content|
+        [content.key, translation_class.find_by(i18n_content_id: content, locale: locale)&.value]
+      end.to_h
+    end
+  end
 end

config/initializers/i18n_translation.rb

@@ -8,10 +8,8 @@ module ActionView
 
       def t(key, options = {})
         current_locale = options[:locale].presence || I18n.locale
+        translation = I18nContent.translations_hash(current_locale)[key]
 
-        i18_content = I18nContent.find_by(key: key)
-        translation = I18nContentTranslation.find_by(i18n_content_id: i18_content&.id,
-                                                     locale: current_locale)&.value
         if translation.present?
           translation % options
         else

spec/models/i18n_content_spec.rb

@@ -118,4 +118,41 @@ RSpec.describe I18nContent, type: :model do
       })
     end
   end
+
+  describe ".translations_hash" do
+    let!(:content) { create(:i18n_content, key: "great", value_en: "Custom great", value_es: nil) }
+
+    it "gets the translations" do
+      expect(I18nContent.translations_hash(:en)["great"]).to eq "Custom great"
+    end
+
+    it "does not use fallbacks, so YAML files will be used instead" do
+      expect(I18nContent.translations_hash(:es)["great"]).to be nil
+    end
+
+    it "gets new translations after values are cached" do
+      expect(I18nContent.translations_hash(:en)["great"]).to eq "Custom great"
+
+      create(:i18n_content, key: "amazing", value_en: "Custom amazing")
+
+      expect(I18nContent.translations_hash(:en)["great"]).to eq "Custom great"
+      expect(I18nContent.translations_hash(:en)["amazing"]).to eq "Custom amazing"
+    end
+
+    it "gets the updated translation after values are cached" do
+      expect(I18nContent.translations_hash(:en)["great"]).to eq "Custom great"
+
+      content.update!(value_en: "New great")
+
+      expect(I18nContent.translations_hash(:en)["great"]).to eq "New great"
+    end
+
+    it "does not get removed translations after values are cached" do
+      expect(I18nContent.translations_hash(:en)["great"]).to eq "Custom great"
+
+      I18nContent.delete_all
+
+      expect(I18nContent.translations_hash(:en)["great"]).to be nil
+    end
+  end
 end