No build task showing

How do I get a build task to show?

`
thufir@mordor:~/petri$
thufir@mordor:~/petri$ gradle tasks
:tasks


All tasks runnable from root project

Build Setup tasks

init - Initializes a new Gradle build. [incubating]
wrapper - Generates Gradle wrapper files. [incubating]

Help tasks

components - Displays the components produced by root project ‘petri’. [incubating]
dependencies - Displays all dependencies declared in root project ‘petri’.
dependencyInsight - Displays the insight into a specific dependency in root project ‘petri’.
help - Displays a help message.
model - Displays the configuration model of root project ‘petri’. [incubating]
projects - Displays the sub-projects of root project ‘petri’.
properties - Displays the properties of root project ‘petri’.
tasks - Displays the tasks runnable from root project ‘petri’.

To see all tasks and more detail, run gradle tasks --all

To see more detail about a task, run gradle help --task

BUILD SUCCESSFUL

Total time: 9.044 secs

This build could be faster, please consider using the Gradle Daemon: http://gradle.org/docs/2.5/userguide/gradle_daemon.html
thufir@mordor:~/petri$
thufir@mordor:~/petri$ cat gradle.build
apply plugin: ‘java’

archiveBaseName = "HelloWorld"
version = “0.5”

thufir@mordor:~/petri$
thufir@mordor:~/petri$ cat src/net/petrikainulainen/gradle/HelloWorld.java
package net.petrikainulainen.gradle;

public class HelloWorld {

public static void main(String[] args) {
    System.out.println("Hello World!");
}

}
thufir@mordor:~/petri$

`