Use redux, react-redux and redux-thunk

Let's add these dependencies to package.json because we plan to use them
to do application state management (redux, react-redux) and API
communication (react-thunk).

Author: ikalnytskyi

package-lock.json

@@ -25,7 +25,10 @@
     "react-codemirror2": "^3.0.7",
     "react-custom-scrollbars": "^4.2.1",
     "react-dom": "^16.0.0",
-    "react-router-dom": "^4.2.2"
+    "react-redux": "^5.0.6",
+    "react-router-dom": "^4.2.2",
+    "redux": "^3.7.2",
+    "redux-thunk": "^2.2.0"
   },
   "devDependencies": {
     "babel-cli": "^6.26.0",