Add bot funcitonality and problems

.gitignore

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+node_modules/
+data/

np-bot.js

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+var Botkit = require('botkit');
+var controller = Botkit.slackbot({
+    json_file_store: process.argv[3]
+});
+var bot = controller.spawn({
+    token: process.argv[2]
+})
+var problems = [
+    {"title": "Travelling salesman problem", "wiki_title": "Travelling_salesman_problem"},
+    {"title": "Knapsack problem", "wiki_title": "Knapsack_problem"},
+    {"title": "Bin packing problem", "wiki_title": "Bin_packing_problem"},
+    {"title": "Partition problem", "wiki_title": "Parition_problem"},
+    {"title": "Longest path problem", "wiki_title": "Longest_path_problem"},
+    {"title": "Longest common subsequence problem"},
+    {"title": "Art gallery problem"},
+    {"title": "Route inspection problem"},
+    {"title": "Open-shop scheduling problem"},
+    {"title": "Calculated minimum spanning tree"}
+]
+
+var last_index = -1;
+
+
+bot.startRTM(function(err,bot,payload) {
+    if (err) {
+        throw new Error('Could not connect to Slack');
+    }
+});
+
+function createData(id) {
+    return {id: id, bot_calls: 0};
+};
+
+function incrementKey(id, key, amount, scope) {
+    controller.storage[scope].get(id, function(err,data) {
+        if (!data) {
+            console.log("Initializing " + scope + " data");
+            data = createData(id);
+        }
+        console.log("Current " + scope + " data:",data);
+        console.log("Incrementing mentions to " + (data[key] + amount));
+        data[key] = data[key] + amount
+        controller.storage[scope].save(data);
+    });
+}
+
+controller.hears(["np"],["direct_message","direct_mention","mention","ambient"],function(bot,message) {
+    console.log(message.user + " mentioned \"np\"");
+
+    // Increment the logged amount of mentions
+    incrementKey(message.user, "bot_calls", 1, "users");
+    incrementKey(message.channel, "bot_calls", 1, "channels");
+    incrementKey(message.team, "bot_calls", 1, "teams");
+
+    // Decide what to do
+    if (Math.random() < 0.9) {
+        var index = Math.floor(Math.random() * problems.length);
+        var base_url = "https://en.wikipedia.org/wiki/";
+        var problem, title, wiki_title;
+
+        // Ensure that the same problem won't get posted twice
+        while (index == last_index && problems.length > 1) {
+            index = Math.floor(Math.random() * problems.length);
+        }
+
+        // Find the problem metadata
+        problem = problems[index];
+        title = problem.title;
+        wiki_title = title.replace(/ /g,"_");
+
+        // Reply with the chosen problem
+        bot.reply(message,"Have you heard about the _" + title + "_? That is an NP-complete problem!\nSee " + base_url + wiki_title + " for more info!");
+        last_index = index;
+    } else {
+        bot.say(
+            {
+                text: '<@U0NEAMJS3|jonbot>, what do you think about NP-complete problems?',
+                channel: message.channel
+            }
+        );
+    }
+
+    // React with appropriate emoji
+    bot.api.reactions.add({
+        timestamp: message.ts,
+        channel: message.channel,
+        name: "mount_fuji",
+    },function(err, res) {
+        if (err) {
+            bot.botkit.log('Failed to add reaction emoji');
+        }
+    });
+});