Add hook to optimize staged SVGs before commit (#166)

scripts/optimizeStagedSvgs.js

@@ -0,0 +1,10 @@
+import fs from 'fs';
+import processSvg from './render/processSvg';
+
+const svgFiles = process.argv.slice(4);
+
+svgFiles.forEach(async svgFile => {
+  const content = fs.readFileSync(svgFile);
+  const svg = await processSvg(content);
+  fs.writeFileSync(svgFile, svg, 'utf-8');
+});