Updated license to GPL

LICENSE

@@ -0,0 +1,16 @@
+GNU GENERAL PUBLIC LICENSE
+
+Copyright (c) 2016 Shaun Burdick
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.

package.json

@@ -17,7 +17,7 @@
     "type": "git",
     "url": "http://github.com/shaunburdick/slack-jirabot.git"
   },
-  "license": "ISC",
+  "license": "GPL-3.0",
   "engine": {
     "node": "^4.0.0"
   },