Update security.md

Hi Guys 
I was reading through this guide last night and noticed a small mistake, would be great if you could update it. 
I changed the word 'building' to 'build' in line 20. 
"Web application frameworks are made to help developers building web applications"
Also dup `column_types` in AR::Result `initialize_copy`
Refer to Rails.env only when Rails is defined
test cases to describe the MySQL boolean behavior.
Unifies mysql and mysql2 casting of booleans.
Merge pull request #12425 from senny/mysql_booleans

Unify boolean quoting for Mysql- and Mysql2Adapter.
Merge pull request #12815 from Adam89/patch-1

Update security.md [ci skip]
Prevent the counter cache from being decremented twice

when destroying a record on a has_many :through association.
:destroy method has own counter_cache callbacks.
documentation updated for Hashes [ci skip]
Merge pull request #12748 from dm1try/fix_counter_cache_for_through_association

Fixes #11079, prevent the counter cache from being decremented twice when destroying a record on a has_many :through association
Merge pull request #12854 from kuldeepaggarwal/f-indentation

methods and outputs indented [ci skip]
updated documentation for Integer
Allow Pathnames to be added to eager load paths
Make static error pages responsive
Merge pull request #12555 from EtienneLem/responsive-static-pages

Make static error pages responsive
Merge pull request #12857 from kuldeepaggarwal/f-indentation

updated documentation for Integer [ci skip]
Include URL helpers in TestController in bug report templates
[ci skip]

Fixes #12848.
Merge pull request #12851 from RKushnir/master

Include URL helpers in TestController in bug report templates [ci skip]
Merge pull request #12695 from mikepack/allow_pathnames

Allow Pathnames to be added to eager load paths
Drop a sqlite_version check because we only support SQLite 3.6.16 or newer.

Drop some comments that document the implementation rather than the interface.