Merge pull request ReactiveX#39 from Kusand/patch-1

Update README.md for gradle dependency example

Author: mttkay

README.md

@@ -31,14 +31,19 @@ Example for Maven:
 <dependency>
     <groupId>io.reactivex</groupId>
     <artifactId>rxandroid</artifactId>
-    <version>0.22</version>
+    <version>0.22.0</version>
 </dependency>
 ```
 
 and for Ivy:
 
 ```xml
-<dependency org="io.reactivex" name="rxandroid" rev="0.22" />
+<dependency org="io.reactivex" name="rxandroid" rev="0.22.0" />
+```
+
+and for Gradle:
+```groovy
+compile 'io.reactivex:rxandroid:0.22.0'
 ```
 
 ## Build