class CmAdmin::Models::Column

def format_header

returns a string value as a header (either field_name or value present in header attribute) 
def format_header
  header_value = if self.header.present?
                   self.header
                 elsif self.field_type.to_s == 'association'
                   self.association_name
                 else
                   self.field_name
                 end
  header_value.to_s.titleize.upcase
end