Update README.md
Merge pull request #1 from zormandi/master

Fixed bundler issues
[SUITEDEV-2114] development dependencies versions
[SUITEDEV-2114] remove ruby-head from travis builds
[SUITEDEV-2114] minimal ruby refactorings
Add Travis-CI badge
[SUITEDEV-2114] use Escher instance, pass options to the instance, refactorings
[SUITEDEV-2114] pass options to the instance, related refactorings
[SUITEDEV-2114] pass options to the instance, related refactorings
[SUITEDEV-2114] add missing test
minor change: add brackets
minor change: add brackets
[SUITEDEV-2114] validating presigned urls (first milestone)
[SUITEDEV-2114] much better presigned url validation
[SUITEDEV-2114] check all(?) required parts of the presigned URL
[SUITEDEV-2114] more developer friendly URL presign parameters
[SUITEDEV-2114] port tests from js: header key order, header value order, header value whitespaces
[SUITEDEV-2114] fix IDE warnings: rename method
[SUITEDEV-2114] fix IDE warnings: unused params
[SUITEDEV-2114] fix IDE warnings: unresolved ruby references