Fix dead url (#353)

Author: aviperl

docs/index.md

@@ -35,7 +35,7 @@ The following describes the layout of the repository and its different artifacts
   * Primary API for building and training neural networks with TensorFlow
   * Intended audience: neural network developers
 
-* [ndarray](https://github.com/tensorflow/java/tree/master/ndarray)
+* [ndarray](https://github.com/tensorflow/java-ndarray)
   * Generic utility library for n-dimensional data I/O operations
   * Used by TensorFlow but does not depend on TensorFlow
   * Intended audience: any developer who needs a Java n-dimensional array implementation, whether or not they