moved android implementation from /app to /android, rnpm link did not find the android implementation from app -directory.

android/src/main/java/com/bitgo/randombytes/RandomBytesModule.java

@@ -0,0 +1,31 @@
+package com.bitgo.randombytes;
+
+import com.facebook.react.bridge.ReactMethod;
+import com.facebook.react.bridge.ReactApplicationContext;
+import com.facebook.react.bridge.Callback;
+
+import com.facebook.react.bridge.ReactContextBaseJavaModule;
+
+import java.security.SecureRandom;
+
+import android.util.Base64;
+
+class RandomBytesModule extends ReactContextBaseJavaModule {
+
+  public RandomBytesModule(ReactApplicationContext reactContext) {
+    super(reactContext);
+  }
+
+  @Override
+  public String getName() {
+    return "RNRandomBytes";
+  }
+  @ReactMethod
+  public void randomBytes(int size, Callback success) {
+    SecureRandom sr = new SecureRandom();
+    byte[] output = new byte[size];
+    sr.nextBytes(output);
+    String string = Base64.encodeToString(output, Base64.DEFAULT);
+    success.invoke(null, string);
+  }
+}