add new python versions to travis build
diff --git a/.travis.yml b/.travis.yml
index 12ebce7..ec14e5a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,10 +7,12 @@
       env: TOXENV=py26
     - python: "2.7"
       env: TOXENV=py27
-    - python: "3.4"
-      env: TOXENV=py34
     - python: "3.5"
-      env: TOXENV=py35,coveralls, docs
+      env: TOXENV=py35
+    - python: "3.6"
+      env: TOXENV=py36,coveralls, docs
+    - python: "3.7"
+      env: TOXENV=py37
     - python: "pypy"
       env: TOXENV=pypy
 before_install: