title: Duplicate classes error on Android RethinkDB implementation
body: <p>Im making an realtime messaging app. I added RethinkDB implementation to gradle and this error flashing:</p>
  
  <pre class="lang-none prettyprint-override"><code>AGPBI: {"kind":"error","text":"Program type already present: org.hamcrest.core.DescribedAs","sources":[{}],"tool":"D8"}
  * What went wrong:
  Execution failed for task ':app:transformDexArchiveWithExternalLibsDexMergerForDebug'.
  
  com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives: 
  Program type already present: org.hamcrest.core.DescribedAs
  </code></pre>
  
  <p>I cant find which other implementation includes hamcrest.core.DescribedAs, so can you help me to find it or solve the problem ?</p>