diff --git a/Gemfile b/Gemfile
index fbc43c0c0..0afebca97 100644
--- a/Gemfile
+++ b/Gemfile
@@ -18,7 +18,8 @@ gem 'figaro', '1.1.1'
 
 # model related
 gem 'pg',                        '0.19.0'
-gem 'ransack',                   '1.5.1' # for searching
+# 1.8 is for Rails < 5.0
+gem 'ransack', '~> 1.8'
 gem 'validates_email_format_of', '1.6.3' # validates email against RFC 2822 and RFC 3696
 gem 'paper_trail', '~> 4.0'
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 6fe1cabd2..8c140d0f0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -216,7 +216,7 @@ GEM
       activesupport (>= 3.0.0)
     keystores (0.4.0)
     libxml-ruby (3.0.0)
-    loofah (2.2.3)
+    loofah (2.3.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.1)
@@ -230,7 +230,7 @@ GEM
       rake
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
-    minitest (5.11.3)
+    minitest (5.12.2)
     monetize (1.9.0)
       money (~> 6.12)
     money (6.12.0)
@@ -256,8 +256,6 @@ GEM
       request_store (~> 1.1)
     pdfkit (0.8.4.1)
     pg (0.19.0)
-    polyamorous (1.3.1)
-      activerecord (>= 3.0)
     pry (0.10.1)
       coderay (~> 1.1.0)
       method_source (~> 0.8.1)
@@ -294,8 +292,8 @@ GEM
       activesupport (>= 4.2.0, < 5.0)
       nokogiri (~> 1.6)
       rails-deprecated_sanitizer (>= 1.0.1)
-    rails-html-sanitizer (1.2.0)
-      loofah (~> 2.2, >= 2.2.2)
+    rails-html-sanitizer (1.3.0)
+      loofah (~> 2.3)
     rails-settings-cached (0.7.2)
       rails (>= 4.2.0)
     railties (4.2.11.1)
@@ -304,12 +302,11 @@ GEM
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rake (12.3.3)
-    ransack (1.5.1)
-      actionpack (>= 3.0)
-      activerecord (>= 3.0)
-      activesupport (>= 3.0)
+    ransack (1.8.10)
+      actionpack (>= 3.0, < 5.2)
+      activerecord (>= 3.0, < 5.2)
+      activesupport (>= 3.0, < 5.2)
       i18n
-      polyamorous (~> 1.1)
     rbtree3 (0.5.0)
     rdoc (4.3.0)
     regexp_parser (1.5.1)
@@ -464,7 +461,7 @@ DEPENDENCIES
   railroady (= 1.3.0)
   rails (= 4.2.11.1)
   rails-settings-cached (= 0.7.2)
-  ransack (= 1.5.1)
+  ransack (~> 1.8)
   rest-client
   sass-rails (= 5.0.6)
   sdoc (= 0.4.1)