update release notes (#48)

* update release notes

* additional fields

* update readme

README.md

@@ -12,7 +12,7 @@ This appender uses [LogzioSender](https://github.com/logzio/logzio-java-sender)
 <dependency>
     <groupId>io.logz.logback</groupId>
     <artifactId>logzio-logback-appender</artifactId>
-    <version>1.0.17</version>
+    <version>1.0.18</version>
 </dependency>
 ```
 
@@ -37,7 +37,7 @@ This appender uses [LogzioSender](https://github.com/logzio/logzio-java-sender)
 ### Parameters
 | Parameter          | Default                              | Explained  |
 | ------------------ | ------------------------------------ | ----- |
-| **token**              | *None*                                 | Your Logz.io token, which can be found under "settings" in your account, If the value begins with `$` then the appender looks for an environment variable with the name specified. For example: `$LOGZIO_TOKEN` will look for environment variable named `LOGZIO_TOKEN` |
+| **token**              | *None*                                 | Your Logz.io token, which can be found under "settings" in your account, If the value begins with `$` then the appender looks for an environment variable or system property with the name specified. For example: `$LOGZIO_TOKEN` will look for environment variable named `LOGZIO_TOKEN` |
 | **logzioType**               | *java*                                 | The [log type](http://support.logz.io/support/solutions/articles/6000103063-what-is-type-) for that appender, it must not contain spaces |
 | **logzioUrl**               | *https://listener.logz.io:8071*                                 | The url that the appender sends to.  If your account is in the EU you must use https://listener-eu.logz.io:8071 |
 | **drainTimeoutSec**       | *5*                                    | How often the appender should drain the buffer (in seconds) |
@@ -123,6 +123,9 @@ Will send a log to Logz.io that looks like this:
 ```
 
 ### Release notes
+ - 1.0.18
+   - added `compressRequests` parameter to enable gzip compression of the logs before they are sent.
+   - added option to inject system property value into additionalFields, logzioUrl and token.
  - 1.0.16 - 1.0.17
    - added `line` parameter to enable printing the line of code that generated this log
  - 1.0.15 - 1.0.16