Merge branch 'travis_jh9.0.1' into dev

Conflicts:
	.travis.yml  (keep travis_jh9.0.1 side)

Author: rkdarst

.travis.yml

@@ -2,7 +2,7 @@
 language: python
 sudo: false
 python:
-    - 3.7
+    - 3.7-dev
     - 3.6
     - 3.5
     - 3.4
@@ -12,7 +12,7 @@ env:
     - JHUB_VER=0.9.1
 matrix:
     include:
-     - python: 3.7
+     - python: 3.7-dev
        env: JHUB_VER=master
     exclude:
      - python: 3.4
@@ -27,6 +27,7 @@ before_install:
 install:
 # Don't let requirements pull in tornado 5 yet except for jupyterhub master
     - if [ $JHUB_VER != "master" -a $JHUB_VER != "0.9.1" ]; then pip install "tornado<5.0"; fi
+    - pip install jsonschema!=3.0.0a1   # issue #110, remove later
     - pip install --pre -f travis-wheels/wheelhouse -r jupyterhub/dev-requirements.txt
     - pip install --pre -e jupyterhub