Add rails_admin_import for easy import in the backoffice.

Gemfile.lock

@@ -91,6 +91,7 @@ GEM
       rack-test (>= 0.6.3)
       regexp_parser (~> 1.5)
       xpath (~> 3.2)
+    charlock_holmes (0.7.7)
     childprocess (3.0.0)
     concurrent-ruby (1.1.7)
     crass (1.0.6)
@@ -237,6 +238,11 @@ GEM
       rails (>= 5.0, < 7)
       remotipart (~> 1.3)
       sassc-rails (>= 1.3, < 3)
+    rails_admin_import (2.2.0)
+      charlock_holmes (~> 0.6)
+      rails (>= 3.2)
+      rails_admin (>= 0.6.6)
+      simple_xlsx_reader (~> 1.0)
     railties (6.0.3.2)
       actionpack (= 6.0.3.2)
       activesupport (= 6.0.3.2)
@@ -269,6 +275,9 @@ GEM
     selenium-webdriver (3.142.7)
       childprocess (>= 0.5, < 4.0)
       rubyzip (>= 1.2.2)
+    simple_xlsx_reader (1.0.4)
+      nokogiri
+      rubyzip
     spring (2.1.0)
     spring-watcher-listen (2.0.1)
       listen (>= 2.7, < 4.0)
@@ -339,6 +348,7 @@ DEPENDENCIES
   puma (~> 4.1)
   rails (~> 6.0.3, >= 6.0.3.2)
   rails_admin (~> 2.0)
+  rails_admin_import (~> 2.2)
   rake
   sass-rails (>= 6)
   selenium-webdriver