install g+

Author: js1010

.travis.yml

@@ -19,7 +19,7 @@ before_install:
   - sudo apt install -y software-properties-common
   - sudo add-apt-repository -y ppa:deadsnakes/ppa
   - sudo apt update
-  - sudo apt install -y python3-pip python3.6
+  - sudo apt install -y python3-pip python3.6 g++
   - pip3 install -U pip
   - pip3 install setuptools
   - pip3 install -r requirements.txt