Fixes to S3 migration

See merge request !1054

Rake task fix

See merge request !1053

Feat/activestorage migration

See merge request !1052

Feat/deploy to heroku

See merge request !1050

Using bundler flags:  rubocop 0.84.0 (was 0.83.0)

Chores/upgrade rails from 5 2 to 6 0

See merge request !1049

Using bundler flags:  rubocop 0.84.0 (was 0.83.0)

Capistrano deployment error:
LoadError: cannot load such file -- webdrivers/chromedriver

Replace autocomplete library

See merge request !1047

Rubocop offense count listing:

220  Minitest/AssertIncludes
179  Layout/ArgumentAlignment
114  Layout/EmptyLineAfterGuardClause
94   Minitest/RefuteIncludes
47   Style/StringLiterals
27   Metrics/BlockLength
26   Layout/ArrayAlignment
19   Layout/SpaceInsideHashLiteralBraces
17   Layout/LineLength
16   Layout/MultilineMethodCallIndentation
14   Layout/ExtraSpacing
13   Layout/IndentationWidth
11   Layout/EmptyLines
9    Layout/ClosingParenthesisIndentation
9    Layout/TrailingWhitespace
9    Metrics/AbcSize
8    Layout/FirstArrayElementIndentation
8    Layout/IndentationConsistency
7    Layout/FirstArgumentIndentation
7    Style/TrailingCommaInArrayLiteral
6    Style/SymbolArray
5    Layout/EmptyLinesAroundBlockBody
5    Layout/TrailingEmptyLines
5    Style/MethodDefParentheses
4    Layout/EndAlignment
4    Metrics/ClassLength
3    Layout/EmptyLinesAroundClassBody
3    Layout/HashAlignment
3    Layout/MultilineMethodCallBraceLayout
3    Layout/SpaceAfterComma
3    Layout/SpaceInsideBlockBraces
3    Metrics/MethodLength
3    Style/MultilineIfModifier
2    Layout/BlockAlignment
2    Layout/EmptyLineBetweenDefs
2    Layout/FirstHashElementIndentation
2    Layout/SpaceAroundOperators
2    Minitest/AssertEqual
2    Style/TrailingCommaInHashLiteral
1    Layout/CommentIndentation
1    Layout/LeadingCommentSpace
1    Layout/MultilineHashBraceLayout
1    Layout/ParameterAlignment
1    Layout/SpaceInsideArrayLiteralBrackets
1    Layout/SpaceInsideParens
1    Lint/RedundantStringCoercion
1    Minitest/RefuteEqual
1    Minitest/RefuteFalse
1    Naming/MethodName
1    Performance/ReverseEach

I only fetch the dependency with yarn here. This is NOT an introduction of webpacker assets!

Rails gem upgrades

See merge request !1044