diff --git a/Gemfile b/Gemfile
index 8469ebc..e1788b9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,9 +5,9 @@ ruby '2.4.2'
 gem 'slack-ruby-bot', '~> 0.10.5'
 gem 'wolfram'
 gem 'puma'
-gem 'sinatra'
+gem 'sinatra', '~> 2.0.2'
 gem 'mechanize'
-gem 'nokogiri'
+gem 'nokogiri', '~> 1.8.2'
 gem 'celluloid-io'
 
 group :development, :test do
diff --git a/Gemfile.lock b/Gemfile.lock
index 3fb8194..f2674d0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,9 +1,9 @@
 GEM
   remote: http://rubygems.org/
   specs:
-    activesupport (5.1.4)
+    activesupport (5.2.0)
       concurrent-ruby (~> 1.0, >= 1.0.2)
-      i18n (~> 0.7)
+      i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
     celluloid (0.17.3)
@@ -28,28 +28,29 @@ GEM
     celluloid-supervision (0.20.6)
       timers (>= 4.1.1)
     concurrent-ruby (1.0.5)
+    connection_pool (2.2.2)
     diff-lcs (1.3)
-    domain_name (0.5.20170404)
+    domain_name (0.5.20180417)
       unf (>= 0.0.5, < 1.0.0)
-    faraday (0.13.1)
+    faraday (0.15.2)
       multipart-post (>= 1.2, < 3)
     faraday_middleware (0.12.2)
       faraday (>= 0.7.4, < 1.0)
-    foreman (0.84.0)
+    foreman (0.85.0)
       thor (~> 0.19.1)
     gli (2.17.1)
     hashie (3.5.7)
-    hitimes (1.2.6)
+    hitimes (1.3.0)
     http-cookie (1.0.3)
       domain_name (~> 0.5)
-    i18n (0.9.1)
+    i18n (1.0.1)
       concurrent-ruby (~> 1.0)
-    mechanize (2.7.5)
+    mechanize (2.7.6)
       domain_name (~> 0.5, >= 0.5.1)
       http-cookie (~> 1.0)
       mime-types (>= 1.17.2)
       net-http-digest_auth (~> 1.1, >= 1.1.1)
-      net-http-persistent (~> 2.5, >= 2.5.2)
+      net-http-persistent (>= 2.5.2)
       nokogiri (~> 1.6)
       ntlm-http (~> 0.1, >= 0.1.1)
       webrobots (>= 0.0.9, < 0.2)
@@ -57,22 +58,23 @@ GEM
       mime-types-data (~> 3.2015)
     mime-types-data (3.2016.0521)
     mini_portile2 (2.3.0)
-    minitest (5.11.1)
+    minitest (5.11.3)
     multipart-post (2.0.0)
-    mustermann (1.0.1)
+    mustermann (1.0.2)
     net-http-digest_auth (1.4.1)
-    net-http-persistent (2.9.4)
-    nio4r (2.2.0)
-    nokogiri (1.8.1)
+    net-http-persistent (3.0.0)
+      connection_pool (~> 2.2)
+    nio4r (2.3.1)
+    nokogiri (1.8.4)
       mini_portile2 (~> 2.3.0)
     ntlm-http (0.1.1)
-    puma (3.11.0)
-    rack (2.0.3)
-    rack-protection (2.0.0)
+    puma (3.12.0)
+    rack (2.0.5)
+    rack-protection (2.0.3)
       rack
-    rack-test (0.8.2)
+    rack-test (1.1.0)
       rack (>= 1.0, < 3)
-    rake (12.3.0)
+    rake (12.3.1)
     rspec (3.7.0)
       rspec-core (~> 3.7.0)
       rspec-expectations (~> 3.7.0)
@@ -85,16 +87,16 @@ GEM
     rspec-mocks (3.7.0)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.7.0)
-    rspec-support (3.7.0)
-    sinatra (2.0.0)
+    rspec-support (3.7.1)
+    sinatra (2.0.3)
       mustermann (~> 1.0)
       rack (~> 2.0)
-      rack-protection (= 2.0.0)
+      rack-protection (= 2.0.3)
       tilt (~> 2.0)
     slack-ruby-bot (0.10.5)
       hashie
       slack-ruby-client (>= 0.6.0)
-    slack-ruby-client (0.11.0)
+    slack-ruby-client (0.11.1)
       activesupport
       faraday (>= 0.9)
       faraday_middleware
@@ -106,11 +108,11 @@ GEM
     tilt (2.0.8)
     timers (4.1.2)
       hitimes
-    tzinfo (1.2.4)
+    tzinfo (1.2.5)
       thread_safe (~> 0.1)
     unf (0.1.4)
       unf_ext
-    unf_ext (0.0.7.4)
+    unf_ext (0.0.7.5)
     webrobots (0.1.2)
     websocket-driver (0.7.0)
       websocket-extensions (>= 0.1.0)
@@ -125,12 +127,12 @@ DEPENDENCIES
   celluloid-io
   foreman
   mechanize
-  nokogiri
+  nokogiri (~> 1.8.2)
   puma
   rack-test
   rake
   rspec
-  sinatra
+  sinatra (~> 2.0.2)
   slack-ruby-bot (~> 0.10.5)
   wolfram
 
@@ -138,4 +140,4 @@ RUBY VERSION
    ruby 2.4.2p198
 
 BUNDLED WITH
-   1.16.1
+   1.16.3