Update to enable views working with SchemaEnforcer

spec/view_spec.cr

@@ -21,7 +21,7 @@ describe "views" do
     nickname_info.count.should eq 3
   end
 
-  pending "works with SchemaEnforcer" do
+  it "works with SchemaEnforcer" do
     AdminUser.ensure_correct_column_mappings!
     NicknameInfo.ensure_correct_column_mappings!
   end

src/avram/model.cr

@@ -73,6 +73,7 @@ abstract class Avram::Model
     setup(Avram::Model.setup_getters)
     setup(Avram::Model.setup_column_info_methods)
     setup(Avram::Model.setup_association_queries)
+    setup(Avram::Model.setup_view_schema_enforcer_validations)
     setup(Avram::BaseQueryTemplate.setup)
     setup(Avram::SchemaEnforcer.setup)
   end
@@ -202,6 +203,11 @@ abstract class Avram::Model
     schema_enforcer_validations << EnsureMatchingColumns.new(model_class: {{ type.id }})
   end
 
+  macro setup_view_schema_enforcer_validations(type, *args, **named_args)
+    schema_enforcer_validations << EnsureExistingTable.new(model_class: {{ type.id }})
+    schema_enforcer_validations << EnsureMatchingColumns.new(model_class: {{ type.id }}, check_required: false)
+  end
+
   macro setup_getters(columns, *args, **named_args)
     {% for column in columns %}
       {% db_type = column[:type].is_a?(Generic) ? column[:type].type_vars.first : column[:type] %}