Add Proguard Config to Readme

[Jogan]

I needed to add:

-dontwarn javax.xml.bind.DatatypeConverter
-dontwarn org.apache.commons.codec.**
-dontwarn com.ning.http.client.**

in order for the library to work with proguard.

[VictorAlbertos]

Hi @Jogan

I don't use proguard. So I'm going to add them to the readme.

Thanks 👍

[jbmlaird]

I'm not sure if OP was using OAuth2 or OAuth1 but in addition to his 3 I had to add

-keep class org.fuckboilerplate.rx_social_connect.internal.persistence.OAuth1AccessToken {
    <fields>;
}

for OAuth1.

[hardwinder]

I had crash when doing OAuth2 authentication while having proguard active. Thanks @jbmlaird for the tip 🍻 Add this to proguard-rules if using OAuth2:

-keep class org.fuckboilerplate.rx_social_connect.internal.persistence.OAuth2AccessToken {
    <fields>;
}