Replace the use of Int for Enums in schema.graphql

[Alann27]

Objective

Replace the use of Int for Enums in schema.graphql.

Origin Document

We replaced the use of enums in the schema.graphql as we thought those fields where being saved in the db with a string type but we were wrong. So why we don't change it back to enums right now?

We need to be able to query some entities by fields that had as a type an enum. To be able to query by those fields, those fields must have the @index directive in the schema.graphql but you cannot use an enum type and the @index directive at the same time (if you do that you will get an error).

For the moment we are going to stick with the Int type but as soon as we found a solution for the problem described previously, we will change the Int types for Enums.

Creator: @Alann27
Co-Owners: @jorgecuesta @bryanchriswhite