Fix production build (#265)

* Fix production build

The production build failing was the result of a bug related to an older version react-scripts not playing nice with the latest version of graphql (graphql/graphql-js#1248).

Updating to the latest version of react-scripts (v2.1.1) fixed the bug. It also reduces the production build *considerably* (from over 1mb down to 48kb).

* Downgrade babel-preset-react-app to 3.1.0

Author: adamsoffer

Diff for: README.md

@@ -24,7 +24,7 @@ The quickest way to run a Graph Node locally is to use the
 This will automatically provision a server with rust, postgres, and ipfs, and
 spin up a graph node with a GraphiQL interface at `http://127.0.0.1:8000/`.
 Congrats, you're now ready to build and deploy the Livepeer subgraph. You may
-skip ahead to [Building & deploying the Subgraph](#building-&-deploying-the-livepeer-subgraph)
+skip ahead to [Building & deploying the Subgraph](#building-and-deploying-the-livepeer-subgraph)
 
 ### Running a local Graph Node _without_ Docker
 
@@ -64,7 +64,7 @@ optional, it depends on your setup.
 
 This will also spin up a GraphiQL interface at `http://127.0.0.1:8000/`.
 
-### Building & deploying the Livepeer Subgraph
+### Building and Deploying the Livepeer Subgraph
 
 Back in our subgraph directory, run