Newbie looking at advice whether to flip or hold

Hey guys, 

I just purchased my second property this year.  All success due to biggerpockets networking, books, and videos.  I am not sure what to do now that I have it. 

I bought an apartment off an online auction for $53,500 (I used cash). 

The apartment comps around $125,000 and I received an offer for $115,000. 

I also found a lender who will give me n equity line for 80% of the appraisal (around $90,000)

It rents long term for $1,100. 

Experienced investors for a newbie looking to have a passive income portfolio. What would you recommend?

Flip and take gains and reinvest?

Or take the equity line and reinvest?

Thanks