code: function updateVariable(key, value) {
              variableService.addOrUpdate({key: key, value: value}, function () {
                  vm.variables[key] = value;
                  vm.variable = {
                      key: undefined,
                      value: undefined
                  };
              });
          }
docs: Update the given variable.
  @param key The key.
  @param value The value.