Add customizable theme

src/client/components/App.js

 import React from 'react';
+import { MuiThemeProvider, createMuiTheme } from '@material-ui/core/styles';
 import MapApp from '../containers/MapApp';
+// import green from '@material-ui/core/colors/green';
+import deepOrange from '@material-ui/core/colors/deepOrange';
+// import red from '@material-ui/core/colors/red';
+// import amber from '@material-ui/core/colors/amber';
+// import grey from '@material-ui/core/colors/grey';
+
+const theme = createMuiTheme({
+  palette: {
+    primary: deepOrange,
+  },
+});
 
 const App = () => (
-  <MapApp />
+  <MuiThemeProvider theme={theme}>
+    <MapApp />
+  </MuiThemeProvider>
 );
 
 export default App;