API Key grants are not removed from Redis

[jgoizueta]

If an API Key is modified and some of its grants removed, this will not be reflected in Redis, because we use HMSET to update the Redis keys (HMSET set the specified fields, any other fields present are left untouched).
We should remove (HDEL) fields not present in the new grants (we could do this by either looking an the record changes or at the Redis hash value.

[jgoizueta]

I think this could be a fix for this: it sets the removed api grants to false:

diff --git a/app/models/carto/api_key.rb b/app/models/carto/api_key.rb
index 3b0566358c..02be25a153 100644
--- a/app/models/carto/api_key.rb
+++ b/app/models/carto/api_key.rb
@@ -503,9 +503,19 @@ module Carto
       @user_db_connection ||= user.in_database
     end

+    def removed_granted_apis
+      if changes[:grants]
+        old_apis, new_apis = changes[:grants].map { |g| g.find { |v| v[:type] == 'apis' }[:apis] }
+        old_apis - new_apis
+      else
+        []
+      end
+    end
+
     def redis_hash_as_array
       hash = ['user', user.username, 'type', type, 'database_role', db_role, 'database_password', db_password]
       granted_apis.each { |api| hash += ["grants_#{api}", true] }
+      removed_granted_apis.each { |api| hash += ["grants_#{api}", false] }
       hash
     end