update readme

Author: lossycache

README.md

@@ -1,2 +1,54 @@
 # OpenWeatherMap w/ golang
-A lightweight wrapper for the OpenWeatherMap API for use with golang
+A lightweight wrapper for the OpenWeatherMap API for use with golang
+
+## Usage
+
+First, create an instance of an OpenWeatherMap struct with your APP ID
+```go
+package main
+import "github.com/ramsgoli/openweathermap"
+
+owm := openweathermap.OpenWeatherMap{API_KEY: os.Getenv("OWM_APP_ID")}
+```
+
+### Fetching the current weather
+
+Create an instance of the CurrentWeatherMap struct. 
+
+If fetching the weather from a specific city, pass the city name as an argument to the CurrentWeatherFromCity function
+```go
+var currentWeather *openweathermap.CurrentWeatherResponse
+var err error
+
+currentWeather, err = owm.CurrentWeatherFromCity(city)
+```
+
+If fetching the weather from geocoordinates, pass the latitude and longitudeas arguments to the CurrentWeatherFromCoordinates function
+```go
+var currentWeather *openweathermap.CurrentWeatherResponse
+var err error
+
+currentWeather, err = owm.CurrentWeatherFromCoordinates(lat, long)
+```
+
+
+This function returns a struct, (CurrentWeatherResonse) that matches the fields of the json response from the API
+```json
+{"coord":{"lon":139,"lat":35},
+"sys":{"country":"JP","sunrise":1369769524,"sunset":1369821049},
+"weather":[{"id":804,"main":"clouds","description":"overcast clouds","icon":"04n"}],
+"main":{"temp":289.5,"humidity":89,"pressure":1013,"temp_min":287.04,"temp_max":292.04},
+"wind":{"speed":7.31,"deg":187.002},
+"rain":{"3h":0},
+"clouds":{"all":92},
+"dt":1369824698,
+"id":1851632,
+"name":"Shuzenji",
+"cod":200}
+```
+
+To access fields of the struct, use the json object's field name with the first letter capitalized
+```go
+fmt.Printf("The current temperature in %s is %.2f degrees\n", currentWeather.Name, currentWeather.Main.Temp)
+```
+