Newcomers_Guide.rst: Add Introduction to Gitter
Newcomers_Guide.rst: Add Introduction to Gitter

Give a simple introduction to Gitter and cobot

Closes https://github.com/coala/coala/issues/3958

coala/coala,shreyans800755/coala,RJ722/coala,Nosferatul/coala,Balaji2198/coala,netman92/coala,nemaniarjun/coala,rimacone/testing2,shreyans800755/coala,aptrishu/coala,karansingh1559/coala,coala-analyzer/coala,rimacone/testing2,aptrishu/coala,netman92/coala,nemaniarjun/coala,Asnelchristian/coala,Balaji2198/coala,damngamerz/coala,nemaniarjun/coala,RJ722/coala,kartikeys98/coala,SanketDG/coala,kartikeys98/coala,CruiseDevice/coala,MariosPanag/coala,jayvdb/coala,Nosferatul/coala,kartikeys98/coala,jayvdb/coala,rimacone/testing2,Asnelchristian/coala,coala-analyzer/coala,Asnelchristian/coala,RJ722/coala,arjunsinghy96/coala,CruiseDevice/coala,netman92/coala,MariosPanag/coala,SanketDG/coala,coala/coala,coala-analyzer/coala,Asalle/coala,MariosPanag/coala,shreyans800755/coala,Nosferatul/coala,Asalle/coala,CruiseDevice/coala,Asalle/coala,coala/coala,aptrishu/coala,arjunsinghy96/coala,jayvdb/coala,arjunsinghy96/coala,karansingh1559/coala,damngamerz/coala,karansingh1559/coala,Balaji2198/coala,SanketDG/coala,damngamerz/coala