Add @property-read tags to parameters class.

[ci skip]

lib/Predis/Connection/Parameters.php

@@ -16,6 +16,24 @@ use InvalidArgumentException;
 /**
  * Connection parameters used to initialize connections to Redis.
  *
+ * The actual list of supported connection parameters depends on the features
+ * supported by each connection backend class (please refer to their specific
+ * documentation), furthermore developers can pass their own custom parameters.
+ *
+ * These are the most common parameters used through the library:
+ *
+ * @property-read string scheme             Connection scheme, such as 'tcp' or 'unix'.
+ * @property-read string host               IP address or hostname of Redis.
+ * @property-read int    port               TCP port on which Redis is listening to.
+ * @property-read string path               Path of a UNIX domain socket file.
+ * @property-read float  timeout            Timeout for the connect() operation.
+ * @property-read float  read_write_timeout Timeout for read() and write() operations.
+ * @property-read bool   async_connect      Performs the connect() operation asynchronously.
+ * @property-read bool   tcp_nodelay        Toggles the Nagle's algorithm for coalescing.
+ * @property-read bool   persistent         Leaves the connection open after a GC collection.
+ * @property-read string password           Password to access Redis (see the AUTH command).
+ * @property-read string database           Database index (see the SELECT command).
+ *
  * @author Daniele Alessandri <suppakilla@gmail.com>
  */
 class Parameters implements ParametersInterface