diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 73143937..4ceda594 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -22,17 +22,17 @@ jobs:
       - uses: actions/checkout@v1
       - run: bash -x script/cibuild 2.7 mysql
 
-  test26postgres:
+  test27postgres:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v1
-      - run: bash -x script/cibuild 2.6 postgres
+      - run: bash -x script/cibuild 2.7 postgres
 
-  test26sqlite:
+  test27sqlite:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v1
-      - run: bash -x script/cibuild 2.6 sqlite
+      - run: bash -x script/cibuild 2.7 sqlite
 
 #      - run: bash -x script/cibuild 2.5 postgres
 #      - run: bash -x script/cibuild 2.7 postgres
diff --git a/Dockerfile b/Dockerfile
index bf82d720..303b86b7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:2.6
+FROM ruby:2.7.1
 
 # throw errors if Gemfile has been modified since Gemfile.lock
 RUN bundle config --global frozen 1
diff --git a/Dockerfile-2.5 b/Dockerfile-2.5
index a3fb50a1..f453241e 100644
--- a/Dockerfile-2.5
+++ b/Dockerfile-2.5
@@ -1,4 +1,4 @@
-FROM ruby:2.5
+FROM ruby:2.5.7
 
 # throw errors if Gemfile has been modified since Gemfile.lock
 RUN bundle config --global frozen 1
@@ -7,14 +7,14 @@ WORKDIR /app
 
 RUN touch /etc/app-env
 
-COPY Gemfile* /app/
-RUN gem install bundler
-RUN bundle install --jobs 4
-
 RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
 RUN echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list
 RUN apt-get update && apt-get install -y yarn
 
+COPY Gemfile* /app/
+RUN gem install bundler
+RUN bundle install --jobs 4
+
 RUN mkdir /app/log
 
 COPY . /app/
diff --git a/Dockerfile-2.7 b/Dockerfile-2.6
similarity index 97%
rename from Dockerfile-2.7
rename to Dockerfile-2.6
index a68b373d..0bef7e0e 100644
--- a/Dockerfile-2.7
+++ b/Dockerfile-2.6
@@ -1,4 +1,4 @@
-FROM ruby:2.7
+FROM ruby:2.6.5
 
 # throw errors if Gemfile has been modified since Gemfile.lock
 RUN bundle config --global frozen 1
@@ -7,14 +7,14 @@ WORKDIR /app
 
 RUN touch /etc/app-env
 
-COPY Gemfile* /app/
-RUN gem install bundler
-RUN bundle install --jobs 4
-
 RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
 RUN echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list
 RUN apt-get update && apt-get install -y yarn
 
+COPY Gemfile* /app/
+RUN gem install bundler
+RUN bundle install --jobs 4
+
 RUN mkdir /app/log
 
 COPY . /app/
diff --git a/Gemfile.lock b/Gemfile.lock
index b43051bb..ed10b406 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -76,7 +76,7 @@ GEM
     acts_as_list (1.0.2)
       activerecord (>= 4.2)
     ast (2.4.1)
-    autoprefixer-rails (10.0.1.0)
+    autoprefixer-rails (10.1.0.0)
       execjs
     backport (1.1.2)
     bcrypt (3.1.16)
@@ -105,7 +105,7 @@ GEM
     diff-lcs (1.4.4)
     docile (1.3.2)
     e2mmap (0.1.0)
-    erubi (1.9.0)
+    erubi (1.10.0)
     execjs (2.7.0)
     factory_bot (6.1.0)
       activesupport (>= 5.0.0)
@@ -142,7 +142,7 @@ GEM
     listen (3.3.3)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
-    loofah (2.7.0)
+    loofah (2.8.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.1)
@@ -153,7 +153,7 @@ GEM
     method_source (1.0.0)
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
-    mime-types-data (3.2020.0512)
+    mime-types-data (3.2020.1104)
     mimemagic (0.3.5)
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
@@ -164,7 +164,7 @@ GEM
     nio4r (2.5.4)
     nokogiri (1.10.10)
       mini_portile2 (~> 2.4.0)
-    nokogumbo (2.0.2)
+    nokogumbo (2.0.4)
       nokogiri (~> 1.8, >= 1.8.4)
     paperclip (6.1.0)
       activemodel (>= 4.2.0)
@@ -172,11 +172,11 @@ GEM
       mime-types
       mimemagic (~> 0.3.0)
       terrapin (~> 0.6.0)
-    parallel (1.19.2)
+    parallel (1.20.1)
     parser (2.7.2.0)
       ast (~> 2.4.1)
     pg (1.2.3)
-    puma (5.1.0)
+    puma (5.1.1)
       nio4r (~> 2.0)
     rack (2.2.3)
     rack-mini-profiler (2.2.0)
@@ -224,7 +224,7 @@ GEM
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     ref (2.0.0)
-    regexp_parser (1.8.2)
+    regexp_parser (2.0.0)
     reverse_markdown (2.0.0)
       nokogiri
     rexml (3.2.4)
@@ -241,7 +241,7 @@ GEM
       rubocop-ast (>= 0.6.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 2.0)
-    rubocop-ast (0.8.0)
+    rubocop-ast (1.3.0)
       parser (>= 2.7.1.5)
     ruby-progressbar (1.10.1)
     safe_yaml (1.0.5)
@@ -286,7 +286,7 @@ GEM
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
     sqlite3 (1.4.2)
-    terminal-table (1.8.0)
+    terminal-table (2.0.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     terrapin (0.6.0)
       climate_control (>= 0.0.3, < 1.0)
@@ -300,7 +300,7 @@ GEM
       rails (>= 5.0)
       safe_yaml (>= 0.8.6)
       sassc
-    tzinfo (1.2.7)
+    tzinfo (1.2.8)
       thread_safe (~> 0.1)
     uglifier (4.2.0)
       execjs (>= 0.3.0, < 3)
@@ -311,7 +311,7 @@ GEM
     websocket-extensions (0.1.5)
     will_paginate (3.3.0)
     yard (0.9.25)
-    zeitwerk (2.4.1)
+    zeitwerk (2.4.2)
 
 PLATFORMS
   ruby
diff --git a/app/controllers/todos_controller.rb b/app/controllers/todos_controller.rb
index 863086a0..57090b8f 100644
--- a/app/controllers/todos_controller.rb
+++ b/app/controllers/todos_controller.rb
@@ -907,7 +907,7 @@ end
   def find_todos_with_tag_expr(tag_expr)
     # optimize for the common case: selecting only one tag
     if @single_tag
-      tag = Tag.where(:name => @tag_name).first
+      tag = current_user.tags.where(:name => @tag_name).first
       tag_id = tag.nil? ? -1 : tag.id
       return current_user.todos.with_tag(tag_id)
     end
diff --git a/test-envs/docker-compose-2.6-mysql.yml b/test-envs/docker-compose-2.6-mysql.yml
index 67e67f17..8af77f50 100644
--- a/test-envs/docker-compose-2.6-mysql.yml
+++ b/test-envs/docker-compose-2.6-mysql.yml
@@ -10,7 +10,7 @@ services:
   web:
     build:
       context: ..
-      dockerfile: Dockerfile
+      dockerfile: Dockerfile-2.6
     environment:
       # These are set in script/ci-build, so we need to pass-thru them.
       RAILS_ENV: $RAILS_ENV
diff --git a/test-envs/docker-compose-2.7-mysql.yml b/test-envs/docker-compose-2.7-mysql.yml
index 58e433ff..67e67f17 100644
--- a/test-envs/docker-compose-2.7-mysql.yml
+++ b/test-envs/docker-compose-2.7-mysql.yml
@@ -10,7 +10,7 @@ services:
   web:
     build:
       context: ..
-      dockerfile: Dockerfile-2.7
+      dockerfile: Dockerfile
     environment:
       # These are set in script/ci-build, so we need to pass-thru them.
       RAILS_ENV: $RAILS_ENV
diff --git a/test-envs/docker-compose-2.6-postgres.yml b/test-envs/docker-compose-2.7-postgres.yml
similarity index 100%
rename from test-envs/docker-compose-2.6-postgres.yml
rename to test-envs/docker-compose-2.7-postgres.yml
diff --git a/test-envs/docker-compose-2.6-sqlite.yml b/test-envs/docker-compose-2.7-sqlite.yml
similarity index 100%
rename from test-envs/docker-compose-2.6-sqlite.yml
rename to test-envs/docker-compose-2.7-sqlite.yml