Add support for modals

https://api.slack.com/block-kit/surfaces/modals

lib/Slack_web_api.js

@@ -147,7 +147,10 @@ module.exports = function(bot, config) {
         'users.lookupByEmail',
         'users.setPhoto',
         'users.profile.get',
-        'users.profile.set'
+        'users.profile.set',
+        'views.open',
+        'views.update',
+        'views.push'
     ];
 
     /**
@@ -224,6 +227,21 @@ module.exports = function(bot, config) {
         slack_api.callAPI('chat.update', options, cb);
     };
 
+    slack_api.views.open = function(options, cb) {
+        sanitizeOptions(options);
+        slack_api.callAPI('views.open', options, cb);
+    };   
+
+    slack_api.views.update = function(options, cb) {
+        sanitizeOptions(options);
+        slack_api.callAPI('views.update', options, cb);
+    };
+
+    slack_api.views.push = function(options, cb) {
+        sanitizeOptions(options);
+        slack_api.callAPI('views.push', options, cb);
+    };      
+
     // specify that files get uploaded using multipart
     slack_api.files.upload = function(options, cb) {
         slack_api.callAPI('files.upload', options, cb, !!options.file);
@@ -246,6 +264,14 @@ module.exports = function(bot, config) {
                 bot.log.error('Could not parse blocks', err);
             }
         }
+        if (options.view && typeof(options.view) != 'string') {
+            try {
+                options.view = JSON.stringify(options.view);
+            } catch (err) {
+                delete options.view;
+                bot.log.error('Could not parse view', err);
+            }
+        }
     }