Update README.md resolves #4

Signed-off-by: Edward Wilde <ewilde@gmail.com>

Author: ewilde

.gitignore

@@ -0,0 +1 @@
+.idea

README.md

@@ -1,2 +1,42 @@
 # go-function-sdk
-An SDK for building functions in Go
+An SDK for building OpenFaaS functions in Go
+
+
+## Installing
+
+Use `go get` to retrieve the SDK to add it to your `GOPATH` workspace, or
+project's Go module dependencies.
+
+	go get github.com/openfaas-incubator/go-function-sdk
+
+To update the SDK use `go get -u` to retrieve the latest version of the SDK.
+
+	go get -u github.com/openfaas-incubator/go-function-sdk
+	
+	
+## Features
+
+### Handler definition
+```go
+type FunctionHandler interface {
+	Handle(req Request) (Response, error)
+}
+```
+
+`FunctionHandler` interface is used by [golang-http](https://github.com/openfaas-incubator/golang-http-template/tree/master/template/golang-http)
+template to define a functions handler
+
+
+### Secrets
+For the time being please use the secrets function from `github.com/openfaas/openfaas-cloud/sdk`
+
+See: https://github.com/openfaas/openfaas-cloud/blob/master/sdk/secrets.go
+
+Usage:
+
+```go
+secret, err := sdk.ReadSecret("MY_SECRET")
+if err != nil {
+    return fmt.Errorf("error reading secret. %v", err)
+}
+```