Add T4 GPU nodes.

content/submitting_jobs/submitting_gpu_jobs.md

@@ -18,6 +18,7 @@ of GPU in your job resource requirements if necessary.
 | Tesla P100, with OPA   | gpu_p100      | 2 nodes - 2 GPUs with 12 GB per node |
 | Tesla V100, with 10GbE | gpu_v100      | 1 node - 4 GPUs with 16 GB per node |
 | Tesla V100, with OPA   | gpu_v100      | 21 nodes - 2 GPUs with 32GB per node |
+| Tesla T4, with IB      | gpu_t4        | 12 nodes - 2 GPUs with 16GB per node |
 
 ### Specifying GPU memory (optional)