add mock recommender service for development, add user-context recommended posts

Gemfile.lock

@@ -237,6 +237,7 @@ GEM
     multi_json (1.13.1)
     multi_xml (0.6.0)
     multipart-post (2.0.0)
+    mustermann (1.0.2)
     naught (1.1.0)
     net-http-digest_auth (1.4.1)
     net-http-persistent (2.9.4)
@@ -274,6 +275,8 @@ GEM
       win32-file (>= 0.7.0)
     public_suffix (3.0.2)
     rack (2.0.5)
+    rack-protection (2.0.3)
+      rack
     rack-test (1.0.0)
       rack (>= 1.0, < 3)
     radix62 (1.0.1)
@@ -354,6 +357,11 @@ GEM
       json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.2)
+    sinatra (2.0.3)
+      mustermann (~> 1.0)
+      rack (~> 2.0)
+      rack-protection (= 2.0.3)
+      tilt (~> 2.0)
     sprockets (3.7.1)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
@@ -485,6 +493,7 @@ DEPENDENCIES
   shoulda-matchers
   simple_form
   simplecov
+  sinatra
   sprockets-rails
   statistics2
   streamio-ffmpeg