chore: Document how to use unix domain sockets. (#1607)

* chore: Document how to use unix domain sockets. Thanks @aleksabl

* fix formatting

docs/documentation/head/connect.md

@@ -473,6 +473,32 @@ Connection conn = DriverManager.getConnection(url);
    `assumeMinServerVersion` with parameter >= 9.4 (backend >= 9.4)</p>
 
 
+<a name="unix sockets"></a>
+## Unix sockets
+
+Aleksander Blomskøld has forked junixsocket and added a [Unix SocketFactory](https://github.com/fiken/junixsocket/blob/master/junixsocket-common/src/main/java/org/newsclub/net/unix/socketfactory/PostgresqlAFUNIXSocketFactory.java) that works with the driver.
+His code can be found at [https://github.com/fiken/junixsocket](https://github.com/fiken/junixsocket).
+
+Dependencies for junixsocket are :
+
+```xml
+<dependency>
+  <groupId>no.fiken.oss.junixsocket</groupId>
+  <artifactId>junixsocket-common</artifactId>
+  <version>1.0.2</version>
+</dependency>
+<dependency>
+  <groupId>no.fiken.oss.junixsocket</groupId>
+  <artifactId>junixsocket-native-common</artifactId>
+  <version>1.0.2</version>
+</dependency>
+```
+Simply add
+`?socketFactory=org.newsclub.net.unix.socketfactory.PostgresqlAFUNIXSocketFactory&socketFactoryArg=[path-to-the-unix-socket]`
+to the connection URL.
+
+For many distros the default path is /var/run/postgresql/.s.PGSQL.5432
+
 <a name="connection-failover"></a>
 ## Connection Fail-over