Add link to mapserver container

[Schneegans]

This resolves #337.

[coveralls]

Pull Request Test Coverage Report for Build 4699698606

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 1.141%

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Totals
Change from base Build 4698806602:	0.0%
Covered Lines:	193
Relevant Lines:	16913

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💛 - Coveralls