title: spring-boot-thin-launcher+gradle add local jar dependency
body: <p>I am using spring-boot-thin-launcher to build a thinjar for my application. I am using gradle as my build tool and I have couple of local jar dependencies which are not available in maven repository which I am including in my build.gradle file as below</p>
  
  <pre><code>**compile fileTree(include: ['*.jar'], dir: 'libs')**
  </code></pre>
  
  <p>I add the below task to build my thin jar</p>
  
  <pre><code>task thinJarSourcesJar(type: Jar, dependsOn: classes) {
      classifier = 'sources'
      from sourceSets.main.allSource
      from configurations.runtime.collect { zipTree(it) }
  }
  </code></pre>
  
  <p>But when I tried to execute the <code>gradlew thinJar</code> task, I do not get any reference to the local jars in the genenerated pom/thin.properties file. These are normal java jars which is not built on maven platform, I neither cannot do a maven install on different machines for these jars. Can someone please help me out on this?</p>