feat: add solium linting to travis, npm script

Author: shrugs

.github/PULL_REQUEST_TEMPLATE.md

@@ -4,6 +4,7 @@
 - [ ] ✅ I've added tests where applicable to test my new functionality.
 - [ ] 📖 I've made sure that my contracts are well-documented.
 - [ ] 🎨 I've run the JavaScript linter (`npm run lint:fix`) and fixed all issues.
+- [ ] 🎨 I've run the Solidity linter (`npm run lint:sol:fix`) and fixed all issues.
 
 <!-- **Does this close any open issues?** If so, list them here. -->
 

.travis.yml

@@ -18,6 +18,7 @@ before_script:
   - truffle version
 script:
   - npm run lint
+  - npm run lint:sol
   - npm run test
 notifications:
   slack: