dont blow up on unsupported column types

Author: ajsharp

lib/generators/gql/gql_generator_base.rb

@@ -27,7 +27,8 @@ def map_model_types(model_name)
 
         klass.columns
           .reject { |col| bt_columns.include?(col.name) }
-          .map { |col| {name: col.name, gql_type: type_map.fetch(col.type)} }
+          .reject { |col| type_map[col.type].nil? }
+          .map { |col| {name: col.name, gql_type: type_map[col.type]} }
       end
     end
   end