Fixing GA tag not included in play domain

The GA tag was not properly included because the index.html file that contained it was overwritten by Webpack's HtmlWebpackPlugin.

front/dist/.gitignore

@@ -1 +1,2 @@
-index.html
+index.html
+index.tmpl.html.tmp

front/templater.sh

@@ -2,7 +2,7 @@
 set -x
 set -o nounset errexit
 template_file_index=dist/index.tmpl.html
-generated_file_index=dist/index.html
+generated_file_index=dist/index.tmpl.html.tmp
 tmp_trackcodefile=/tmp/trackcode
 
 # To inject tracking code, you have two choices:

front/webpack.config.js

@@ -39,7 +39,7 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin(
             {
-                template: './dist/index.tmpl.html',
+                template: './dist/index.tmpl.html.tmp',
                 minify: {
                     collapseWhitespace: true,
                     keepClosingSlash: true,