Add relational transports to README

Signed-off-by: Tomasz Maruszak <maruszaktomasz@gmail.com>

Author: zarusz

README.md

@@ -129,6 +129,7 @@ The configuration can be [modularized](docs/intro.md#modularization-of-configura
   - [MQTT](docs/provider_mqtt.md)
   - [Memory](docs/provider_memory.md)
   - [NATS](docs/provider_nats.md)
+  - [PostgreSQL](docs/provider_postgresql.md)
   - [RabbitMQ](docs/provider_rabbitmq.md)
   - [Redis](docs/provider_redis.md)
   - [SQL](docs/provider_sql.md)
@@ -155,9 +156,10 @@ The configuration can be [modularized](docs/intro.md#modularization-of-configura
 | `.Host.MQTT`                         | Transport provider for MQTT                                                                                         | [![NuGet](https://img.shields.io/nuget/v/SlimMessageBus.Host.MQTT.svg)](https://www.nuget.org/packages/SlimMessageBus.Host.MQTT)                                                 |
 | `.Host.Memory`                       | Transport provider implementation for in-process (in memory) message passing (no messaging infrastructure required) | [![NuGet](https://img.shields.io/nuget/v/SlimMessageBus.Host.Memory.svg)](https://www.nuget.org/packages/SlimMessageBus.Host.Memory)                                             |
 | `.Host.NATS`                         | Transport provider for [NATS](https://nats.io/)                                                                     | [![NuGet](https://img.shields.io/nuget/v/SlimMessageBus.Host.NATS.svg)](https://www.nuget.org/packages/SlimMessageBus.Host.NATS)                                                 |
+| `.Host.PostgreSql`                   | Transport provider implementation for PostgreSQL database message passing                                            | [![NuGet](https://img.shields.io/nuget/v/SlimMessageBus.Host.PostgreSql.svg)](https://www.nuget.org/packages/SlimMessageBus.Host.PostgreSql)                                     |
 | `.Host.RabbitMQ`                     | Transport provider for RabbitMQ                                                                                     | [![NuGet](https://img.shields.io/nuget/v/SlimMessageBus.Host.RabbitMQ.svg)](https://www.nuget.org/packages/SlimMessageBus.Host.RabbitMQ)                                         |
 | `.Host.Redis`                        | Transport provider for Redis                                                                                        | [![NuGet](https://img.shields.io/nuget/v/SlimMessageBus.Host.Redis.svg)](https://www.nuget.org/packages/SlimMessageBus.Host.Redis)                                               |
-| `.Host.Sql` (pending)                | Transport provider implementation for SQL database message passing                                                  | [![NuGet](https://img.shields.io/nuget/v/SlimMessageBus.Host.Sql.svg)](https://www.nuget.org/packages/SlimMessageBus.Host.Sql)                                                   |
+| `.Host.Sql`                          | Transport provider implementation for SQL Server / Azure SQL database message passing                               | [![NuGet](https://img.shields.io/nuget/v/SlimMessageBus.Host.Sql.svg)](https://www.nuget.org/packages/SlimMessageBus.Host.Sql)                                                   |
 | **Serialization**                    |                                                                                                                     |                                                                                                                                                                                  |
 | `.Host.Serialization.Json`           | Serialization plugin for JSON (Newtonsoft.Json library)                                                             | [![NuGet](https://img.shields.io/nuget/v/SlimMessageBus.Host.Serialization.Json.svg)](https://www.nuget.org/packages/SlimMessageBus.Host.Serialization.Json)                     |
 | `.Host.Serialization.SystemTextJson` | Serialization plugin for JSON (System.Text.Json library)                                                            | [![NuGet](https://img.shields.io/nuget/v/SlimMessageBus.Host.Serialization.SystemTextJson.svg)](https://www.nuget.org/packages/SlimMessageBus.Host.Serialization.SystemTextJson) |