#125 - First draft of R2DBC benchmarks.

TODOs:

- Review interaction with the JDBC auto-configuration
- Wait for tcp protocol of H2 to be supported
- Wait for Postgres to accept credentialless connections (see [0])

[0] https://github.com/r2dbc/r2dbc-postgresql/issues/125

benchmark/relational/src/main/resources/application-postgres.properties

@@ -2,3 +2,6 @@ spring.datasource.url=jdbc:postgresql://localhost:5432/benchmark
 spring.datasource.platform=postgres
 spring.datasource.initialization-mode=always
 
+spring.r2dbc.url=r2dbc:postgresql://localhost:5432/benchmark
+spring.r2dbc.platform=postgres
+spring.r2dbc.initialization-mode=always