Renaming the readme to index (#308)

Author: jaygambetta

community/teach_me_qiskit_2018/README.ipynb renamed to community/teach_me_qiskit_2018/index.ipynb

@@ -86,7 +86,7 @@
     "#### 3.5 [Developing Quantum Applications with Qiskit Aqua](community/aqua/)\n",
     "Learn how to develop and the fundamentals of quantum applications using Qiskit Aqua\n",
     "\n",
-    "#### 3.6 [Teach Me Qiskit 2018](community/teach_me_qiskit_2018/README.ipynb)\n",
+    "#### 3.6 [Teach Me Qiskit 2018](community/teach_me_qiskit_2018/index.ipynb)\n",
     "Learn from the great contributions to the [Teach Me Qiskit](https://qe-awards.mybluemix.net/) Award.\n",
     "\n",
     "\n",