code: @JsonIgnore
      public void addAttributeMapping(String key, Object value) {
          attributeMappings.put(key, value);
      }
docs: adds an attribute mapping, where the key is known to the UAA and the value represents
  the attribute name on the IDP
  @param key - known to the UAA, such as {@link #EMAIL_ATTRIBUTE_NAME}, {@link #GROUP_ATTRIBUTE_NAME}, {@link #PHONE_NUMBER_ATTRIBUTE_NAME}
  @param value - the name of the attribute on the IDP side, for example <code>emailAddress</code>