Add institutional partners (#4)

Author: jorisvandenbossche

people.md

@@ -34,3 +34,10 @@ Wes McKinney is the Benevolent Dictator for Life (BDFL).
 - Joris Van den Bossche
 - Camille Scott
 - Nathaniel Smith
+
+## Institutional Partners
+
+### Tier 1
+
+- [Continuum Analytics](https://www.continuum.io/) (Jeff Reback, Joris Van den Bossche)
+- [Two Sigma](https://www.twosigma.com/) (Wes McKinney, Phillip Cloud)