Added support for IP2Location.io API (#58)

* Added support for IP2Location.io API

* Update lookup.ex

README.md

@@ -65,6 +65,16 @@ config :geoip, provider: :ipstack, api_key: "your-api-key"
 config :geoip, provider: :ipinfo, api_key: "your-api-key"
 ```
 
+#### IP2Location.io
+
+[IP2Location.io](https://ip2location.io) does not support lookup by hostname (only ip address), therefore the above examples where a hostname is used will return an error.
+
+NOTE: Translation for certain columns is available for Plus and Security plan. You can visit the Parameters section in [https://www.ip2location.io/ip2location-documentation](https://www.ip2location.io/ip2location-documentation) for more information
+
+```elixir
+config :geoip, provider: :ip2locationio, api_key: "your-api-key"
+```
+
 #### test
 
 Provides an easy way to provide mock lookup data in test environments.

lib/geoip/lookup.ex

@@ -81,6 +81,10 @@ defmodule GeoIP.Lookup do
     do:
       "#{http_protocol()}://ipinfo.io/#{host}/json?token=#{Config.api_key()}#{Config.extra_params()}"
 
+  defp lookup_url(host, :ip2locationio),
+    do:
+      "#{http_protocol()}://api.ip2location.io/?key=#{Config.api_key()}&ip=#{host}#{Config.extra_params()}"
+
   defp lookup_url(_host, provider) do
     raise ArgumentError,
           "Unknown provider: '#{inspect(provider)}'. Please check your geoip configuration."