Add usecase and install example to readme

README.md

@@ -2,9 +2,19 @@
 
 This is an openwrt feed that contains definitions to include CoreDNS software into your OpenWRT build.
 
-## how to add the feed into your build
+## install from a binary
 
-> see for details: https://openwrt.org/docs/guide-developer/feeds
+### by using terminal
+1. download an ipk file from the releases page https://code.tokarch.uk/mainnika/openwrt-feed-coredns/releases
+2. put the file to the device, e.g. path `/tmp/coredns.ipk` use scp -- `scp coredns_1.8.6-1_arm_cortex-a7_neon-vfpv4.ipk root@[openwrt-ip]:/tmp/coredns.ipk`
+2. use opkg to install the downloaded file, e.g. `opkg install /tmp/coredns.ipk`
+
+### by using luci
+1. download an ipk file from the releases page https://code.tokarch.uk/mainnika/openwrt-feed-coredns/releases
+2. open luci admin gui and go `System` → `Software`
+3. use `Upload Package` buttom to upload local release file 
+
+## how to add the feed into your build
 
 1. open your feeds.conf.default and add the following line:
 
@@ -18,6 +28,8 @@ This is an openwrt feed that contains definitions to include CoreDNS software in
 
    `./scripts/feeds install -a -p feed_coredns`
 
+> see for details: https://openwrt.org/docs/guide-developer/feeds
+
 ## service init
 
 The package setups an init script `/etc/init.d/coredns` and uci config section:
@@ -43,3 +55,23 @@ The empty `Corefile`:
 . { }
 ```
 
+To configure the coredns instance properly set Corefile with your content.
+
+## use cases
+
+### openwrt hardware as the external dns resolver
+
+> I assume that in this setup openwrt act as a dhcp client (not a server).
+> You can set lan network as a dhcp client by using these uci values (use `uci commit` to apply):
+> ```
+> uci del network.lan.ipaddr
+> uci del network.lan.netmask
+> uci del network.lan.ip6assign
+> uci set network.lan.proto='dhcp'
+> ```
+
+the main goal is to replace `dnsmasq` with `coredns` because they share the same port `53`.
+
+1. go `System` → `Startup`, disable and stop `dnsmasq`
+2. enable and start `coredns`
+3. now coredns acts as a default resolver and listen all interfaces by default.