clientID: process.env.FACEBOOK_ID,

clientSecret: process.env.FACEBOOK_SECRET,
callbackURL: ‘/auth/facebook/callback’,
passReqToCallback: true
},

github: {
clientID: process.env.GITHUB_ID,
clientSecret: process.env.GITHUB_SECRET,
callbackURL: ‘/auth/github/callback’,
passReqToCallback: true
},

twitter: {
consumerKey: process.env.TWITTER_KEY,
consumerSecret: process.env.TWITTER_SECRET,
token: process.env.TWITTER_TOKEN,
tokenSecret: process.env.TWITTER_TOKEN_SECRET,
callbackURL: ‘/auth/twitter/callback’,
passReqToCallback: true
},

google: {
clientID: process.env.GOOGLE_ID,
clientSecret: process.env.GOOGLE_SECRET,
callbackURL: ‘/auth/google/callback’,
passReqToCallback: true
},

linkedin: {
clientID: process.env.LINKEDIN_ID,
clientSecret: process.env.LINKEDIN_SECRET,
callbackURL: ‘/auth/linkedin/callback’,
scope: [‘r_basicprofile’, ‘r_emailaddress’],
passReqToCallback: true
},
slackHook: process.env.SLACK_WEBHOOK,

cookieSecret: process.env.COOKIE_SECRET
};

https://www.youtube.com/watch?v=Jqn_wjkSZwo&feature=share