added pointer/stub for ei-rnn song-et-al in museum doc

Author: Alexander Ororbia

docs/museum/eirnn_song_etal2016.md

@@ -0,0 +1,12 @@
+# Excitatory-Inhibitory Recurrent Neural Network (Song et al.; 2016)
+
+In this exhibit, we create, simulate, and visualize the dynamics and adaptation of the excitatory-inhibitory 
+recurrent neural network (EI-RNN) originally proposed in (Song et al., 2016) [1]. 
+
+The model code for this exhibit can be found 
+[here](https://github.com/NACLab/ngc-museum/tree/main/exhibits/ei_rnn).
+
+<!-- references -->
+## References
+<b>[1]</b> Song, H. F., Yang, G. R., & Wang, X. J. Training excitatory-inhibitory recurrent neural networks 
+for cognitive tasks: a simple and flexible framework. PLoS computational biology, 12(2), e1004792 (2016).

docs/museum/index.rst

@@ -16,6 +16,7 @@ of detailed walkthroughs presented in the table of contents below.)
 
   sparse_coding
   pc_rao_ballard1999
+  eirnn_song_etal2016
   snn_dc
   event_stdp_patches
   rl_snn