title: NanoHTTPD - unable to add gradle dependency
body: <p>I am trying to add <a href="https://github.com/NanoHttpd/nanohttpd" rel="nofollow noreferrer">NanoHTTPD</a> to my Android project.</p>
  
  <p>As mentioned in README.md, I added </p>
  
  <pre><code>dependencies {
      runtime(
         [group: 'org.nanohttpd', name: 'nanohttpd', version: '2.3.1'],
      )
  }
  </code></pre>
  
  <p>it is giving error:</p>
  
  <pre><code>Could not find method runtime() for arguments [{group=org.nanohttpd, name=nanohttpd, version=2.3.1}] on object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.
  </code></pre>
  
  <p>I also tried adding</p>
  
  <pre><code>repositories {
      mavenCentral()
  }
  </code></pre>
  
  <p>mentioned elsewhere, but same error.</p>
  
  <p>I tried the usual way:</p>
  
  <pre><code>implementation 'org.nanohttpd.nanohttpd:2.3.1'
  </code></pre>
  
  <p>it gives error:</p>
  
  <pre><code>Failed to resolve: org.nanohttpd.nanohttpd:2.3.1:
  </code></pre>
  
  <p>I am using Android Studio 3.2.1 
  There seem to be so many people happily using it in Android. What am I missing?</p>