added favicon HOW TO guide

client/public/favicon_SETUP.md

@@ -0,0 +1,38 @@
+# Favicon SETUP
+
+1. Go to [https://favicon.io](https://favicon.io)
+2. Generate an icon pack
+3. Drop all images in `/client/public/`
+4. And configure these 2 files:
+
+### manifest.json:
+
+```
+"icons": [
+  {
+    "src": "favicon.ico",
+    "sizes": "64x64 32x32 24x24 16x16",
+    "type": "image/x-icon"
+  },
+  {
+    "src":"android-chrome-192x192.png",
+    "sizes":"192x192",
+    "type":"image/png"
+  },
+  {
+    "src":"android-chrome-512x512.png",
+    "sizes":"512x512",
+    "type":"image/png"
+  }
+],
+```
+
+### index.html:
+
+```
+<link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
+<link rel="icon" type="image/x-icon" href="%PUBLIC_URL%/favicon.ico" />
+<link rel="icon" type="image/png" sizes="16x16" href="%PUBLIC_URL%/favicon-16x16.png" />
+<link rel="icon" type="image/png" sizes="32x32" href="%PUBLIC_URL%/favicon-32x32.png" />
+<link rel="apple-touch-icon" type="image/png" sizes="180x180" href="%PUBLIC_URL%/apple-touch-icon.png" />
+```