Fix part of #116

[SanjayDevTech]

Explanation

I have implemented group chat community feature.
Used Realtime database to fetch chats and used Firebase-UI to display
Since this PR won't contain full fledged chat feature but it covers the basic functionality of chat.
This PR Fixes part of #116

Checklist

• The PR title starts with "Fix #bugnum: ", followed by a short, clear summary of the changes. (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
• The PR explanation includes the words "Fixes #bugnum: ..." (or "Fixes part of #bugnum" if the PR only partially fixes an issue).
• The PR does not contain any unnecessary auto-generated code from Android Studio.
• The PR does not break any part of the existing code.
• The PR creator have carefully read & adher to the contributing guidelines of the project.
• The PR is made to the branch that's called "develop".
• The PR is made from a branch that is up-to-date with "develop".

[SanjayDevTech]

This is the structure of the msg in the database.
content => Actual text content
createdTime => The timestamp at which the msg was sent
msgId => The key of the msg object
senderId => UId of the sender
senderName => Name of the sender (This can be retrieved from getDisplayName() method of FirebaseUser class.. This works only for Google or any other social login... It won't work for Email password validation)

[riturajjain2000]

Remove build.gradle achanges

Also remove the 'Community' text from the top and make the send button yellow instead of red

Rest looks good

[SanjayDevTech]