Downgraded Ruby to 2.6.5

.ruby-version

@@ -1 +1 @@
-2.7.0-preview1
+2.6.5

.travis.yml

@@ -1,6 +1,6 @@
 language: ruby
 rvm:
-  - "2.7.0-preview1"
+  - "2.6.5"
 
 before_install:
   - "phantomjs --version"

Dockerfile

@@ -1,4 +1,4 @@
-FROM ruby:2.7.0-preview1
+FROM ruby:2.6.5
 RUN apt-get update -qq && apt-get install -y build-essential libpq-dev nodejs
 RUN mkdir /myapp
 WORKDIR /myapp

Gemfile

@@ -4,7 +4,7 @@ source "https://rubygems.org"
 #don't upgrade
 gem "rails", "6.0.0"
 
-ruby "2.7.0"
+ruby "2.6.5"
 
 gem "aruba"
 gem "bcrypt"

Gemfile.lock

@@ -389,7 +389,7 @@ DEPENDENCIES
   unicorn
 
 RUBY VERSION
-   ruby 2.7.0p-1
+   ruby 2.6.5p114
 
 BUNDLED WITH
-   2.1.0.pre.2
+   1.17.3