fix(serializer): serialize only the foreignKeys of belongsTo relations (#587)

Author: nicolasalexandre9

app/serializers/forest_liana/serializer_factory.rb

@@ -369,7 +369,6 @@ def serializer_association(association)
 
     def attributes(active_record_class)
       return [] if @is_smart_collection
-
       active_record_class.column_names.select do |column_name|
         !association?(active_record_class, column_name)
       end
@@ -410,7 +409,7 @@ def association?(active_record_class, column_name)
 
     def foreign_keys(active_record_class)
       begin
-        SchemaUtils.associations(active_record_class).map(&:foreign_key)
+        SchemaUtils.belongs_to_associations(active_record_class).map(&:foreign_key)
       rescue => err
         # Association foreign_key triggers an error. Put the stacktrace and
         # returns no foreign keys.

app/services/forest_liana/schema_utils.rb

@@ -18,6 +18,12 @@ def self.one_associations(active_record_class)
       end
     end
 
+    def self.belongs_to_associations(active_record_class)
+      self.associations(active_record_class).select do |x|
+        [:belongs_to].include?(x.macro)
+      end
+    end
+
     def self.many_associations(active_record_class)
       self.associations(active_record_class).select do |x|
         [:has_many, :has_and_belongs_to_many].include?(x.macro)