how do I pass a string for the relationship in a query?

[angelacode]

Neography::SyntaxException: Parameter maps cannot be used in MATCH patterns (use a literal map instead, eg. "{id: {param}.id}") (line 1, column 21 (offset: 20))
"MATCH (fromNode)-[{relationship}]->(toNode) "

My match statement has an error, even though I pass the value to the relationship string:

query_response = @neo.execute_query("MATCH (fromNode)-[{relationship}]->(toNode)
WHERE fromNode.bot_client_id = {bot_client_id} AND toNode.epoch_utc_i > {fromTime} AND toNode.epoch_utc_i < {toTime}

                                        RETURN  toNode.value
                                        LIMIT   {limit}", 
                                        {
                                            :fromTime => fromTime, :toTime => toTime, :bot_client_id => @bot_client_id, 
                                            :limit => limit, :relationship => relationship.to_sym
                                        }
                                    )

[maxdemarzi]

@neo.execute_query("MATCH (fromNode)-[:" +relationship + "]->(toNode)
WHERE fromNode.bot_client_id = {bot_client_id} AND toNode.epoch_utc_i > {fromTime} AND toNode.epoch_utc_i < {toTime}"

[maxdemarzi]

You can't use a parameter for a relationship type.