add link to expecte JSON-RPC api

Author: pipermerriam

docs/guides/trinity/quickstart.rst

@@ -131,10 +131,21 @@ latest block by calling ``w3.eth.getBlock('latest')``.
   'size': 544,
   'transactions': []})
 
+You can attach to an existing trinity process using the ``attach`` comand.
+
+.. code:: sh
+
+  trinity attach
+
+For a list of JSON-RPC endpoints which are expected to work, see this issue: https://github.com/ethereum/py-evm/issues/178
+
+
+
+
 .. warning::
 
   Trinity is currently in public alpha. **Keep in mind**:
 
   - It is expected to have bugs and is not meant to be used in production
   - Things may be ridiculously slow or not work at all
-  - Only a subset of JSON-RPC API calls are currently supported
+  - Only a subset of JSON-RPC API calls are currently supported