Adding dependencies to a custom gradle plugin

I'm creating a gradle plugin that uses gson, but when I use the plugin at my client it throws this java.lang.NoClassDefFoundError: com/google/gson/Gson I expect I am linking my dependencies in the plugin in a wrong way, but i'm not quite sure so any help would be great.

The build.gradle in the plugin

group 'nl.daanluttik.gradle'
version '0.1'

apply plugin: 'java'
apply plugin: 'maven' // the plugin to distribute to maven

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    compile group: 'com.google.code.gson', name: 'gson', version: '1.7.2'
    compile gradleApi()/*The gradle plugin api*/
    testCompile group: 'junit', name: 'junit', version: '4.11'
}

//To distribute to maven
uploadArchives {
    repositories {
        mavenLocal()
    }
}

A segment of the buildgradle in the client project

buildscript {
    repositories {
        mavenLocal()
    }
    dependencies {
        classpath group: 'nl.daanluttik.gradle', name: 'peach', version: '0.1'
    }
}