Add auth method to simplify (o)authorization

Change-Id: I318e27375dfece96d0d80f35cd2c2b5bb3b167df
diff --git a/man/persistAccessToken-KorAPConnection-method.Rd b/man/persistAccessToken-KorAPConnection-method.Rd
new file mode 100644
index 0000000..b66457e
--- /dev/null
+++ b/man/persistAccessToken-KorAPConnection-method.Rd
@@ -0,0 +1,32 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/KorAPConnection.R
+\name{persistAccessToken,KorAPConnection-method}
+\alias{persistAccessToken,KorAPConnection-method}
+\alias{persistAccessToken}
+\title{Persist current access token in keyring}
+\usage{
+\S4method{persistAccessToken}{KorAPConnection}(kco, accessToken = kco@accessToken)
+}
+\arguments{
+\item{kco}{KorAPConnection object}
+
+\item{accessToken}{access token to be persisted. If not supplied, the current access token of the KorAPConnection object will be used.}
+}
+\value{
+KorAPConnection object.
+}
+\description{
+Persist current access token in keyring
+}
+\examples{
+\dontrun{
+kco <- new("KorAPConnection", accessToken="e739u6eOzkwADQPdVChxFg")
+persistAccessToken(kco)
+
+kco <- new("KorAPConnection") \%>\% auth(app_id="<my application id>") \%>\% persistAccessToken()
+}
+
+}
+\seealso{
+\code{\link[=clearAccessToken]{clearAccessToken()}}, \code{\link[=auth]{auth()}}
+}