add collaborators

Author: max-mapper

collaborators.md

@@ -0,0 +1,8 @@
+## Collaborators
+
+level.js is only possible due to the excellent work of the following collaborators:
+
+<table><tbody><tr><th align="left">maxogden</th><td><a href="https://github.com/maxogden">GitHub/maxogden</a></td></tr>
+<tr><th align="left">juliangruber</th><td><a href="https://github.com/juliangruber">GitHub/juliangruber</a></td></tr>
+<tr><th align="left">mcollina</th><td><a href="https://github.com/mcollina">GitHub/mcollina</a></td></tr>
+</tbody></table>