trying more recent Sinatra gem for resque-web

Gemfile

@@ -23,6 +23,8 @@ gem 'resque-web', require: 'resque_web'
 gem 'rsolr', '~> 1.0'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
+# Need to constrain the version of Sinatra for resque-web, see https://github.com/sinatra/sinatra/issues/1055
+gem 'sinatra', '2.0.0.rc2'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 gem 'therubyracer'

Gemfile.lock

@@ -447,6 +447,7 @@ GEM
     multi_json (1.12.1)
     multi_xml (0.6.0)
     multipart-post (2.0.0)
+    mustermann (1.0.0)
     nest (2.1.0)
       redic
     net-scp (1.2.1)
@@ -486,6 +487,8 @@ GEM
       nokogiri (~> 1.6)
       rails (>= 4.2.0, < 6.0)
     rack (2.0.1)
+    rack-protection (2.0.0.rc2)
+      rack
     rack-test (0.6.3)
       rack (>= 1.0)
     rails (5.0.2)
@@ -643,8 +646,11 @@ GEM
       json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.0)
-    sinatra (1.0)
-      rack (>= 1.0)
+    sinatra (2.0.0.rc2)
+      mustermann (= 1.0.0)
+      rack (~> 2.0)
+      rack-protection (= 2.0.0.rc2)
+      tilt (~> 2.0)
     skydrive (1.2.0)
       activesupport
       httmultiparty
@@ -770,6 +776,7 @@ DEPENDENCIES
   rspec-rails (~> 3.5)
   sass-rails (~> 5.0)
   shoulda-matchers
+  sinatra (= 2.0.0.rc2)
   solr_wrapper (>= 0.3)
   spring
   spring-watcher-listen (~> 2.0.0)