Adds Blogpost into Readme and updates python packages

[gurkanindibay]

There are two issues addresses in this PR

1. Readme update including recent blogpost published about django-multi-tenant
2. Updates django package versions to fix dependabot issues

[codecov[bot]]

Codecov Report

Merging #180 (883e2a8) into main (2bbfddf) will not change coverage. The diff coverage is n/a.

@@            Coverage Diff            @@
##              main      #180   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           44        44           
  Lines         1193      1193           
=========================================
  Hits          1193      1193           

Impacted Files	Coverage Δ
...jango_multitenant/tests/migrations/0001_initial.py	100.00% <ø> (ø)
...tenant/tests/migrations/0010_auto_20190517_1514.py	100.00% <ø> (ø)
...tenant/tests/migrations/0014_auto_20190828_1314.py	100.00% <ø> (ø)
...tenant/tests/migrations/0015_auto_20190829_1334.py	100.00% <ø> (ø)
...tenant/tests/migrations/0017_auto_20200128_0853.py	100.00% <ø> (ø)
...tenant/tests/migrations/0018_auto_20200128_0902.py	100.00% <ø> (ø)
...tenant/tests/migrations/0023_auto_20200412_0603.py	100.00% <ø> (ø)
.../0024_business_tenant_alter_account_id_and_more.py	100.00% <ø> (ø)
...ngo_multitenant/tests/migrations/0025_data_load.py	100.00% <ø> (ø)
...roduct_purchase_store_alter_account_id_and_more.py	100.00% <ø> (ø)
... and 5 more

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