Add citation to the About section

[cjmyers]

Citation

If you use SynBioHub, please cite the following paper:

<ADD SBH CITE HERE>

Additional references for SynBioHub are available here <link to References section>

Contributors

[PRUBHTEJ]

Addressed this issue. Kindly have a look.

[cjmyers]

meant to add:

McLaughlin, James Alastair, et al. “SynBioHub: a standards-enabled design repository for synthetic biology." ACS synthetic biology 7.2 (2018): 682-688.