fix broken Slack link (#316)

README.md

@@ -11,7 +11,7 @@
     <a href='https://lux-api.readthedocs.io/en/latest/?badge=latest'>
         <img src='https://readthedocs.org/projects/lux-api/badge/?version=latest' alt='Documentation Status'  align="center"/>
     </a>
-    <a href='https://lux-project.slack.com/join/shared_invite/zt-lilu4e87-TM4EDTq9HWzlDRycFsrkLg'>
+    <a href='https://communityinviter.com/apps/lux-project/lux'>
         <img src='https://img.shields.io/static/v1?label=chat&logo=slack&message=Slack&color=brightgreen' alt='Slack'  align="center"/>
     </a>
     <a href='https://forms.gle/XKv3ejrshkCi3FJE6'>
@@ -179,5 +179,5 @@ Other additional resources:
 - Sign up for the early-user [mailing list](https://forms.gle/XKv3ejrshkCi3FJE6) to stay tuned for upcoming releases, updates, or user studies. 
 - Visit [ReadTheDoc](https://lux-api.readthedocs.io/en/latest/) for more detailed documentation.
 - Try out these hands-on [exercises](https://mybinder.org/v2/gh/lux-org/lux-binder/master?urlpath=tree/exercise) or [tutorials](https://mybinder.org/v2/gh/lux-org/lux-binder/master?urlpath=tree/tutorial) on [Binder](https://mybinder.org/v2/gh/lux-org/lux-binder/master). Or clone and run [lux-binder](https://github.com/lux-org/lux-binder) locally.
-- Join our community [Slack](https://lux-project.slack.com/join/shared_invite/zt-lilu4e87-TM4EDTq9HWzlDRycFsrkLg) to discuss and ask questions.
+- Join our community [Slack](https://communityinviter.com/apps/lux-project/lux) to discuss and ask questions.
 - Report any bugs, issues, or requests through [Github Issues](https://github.com/lux-org/lux/issues). 

doc/source/guide/FAQ.rst

@@ -12,7 +12,7 @@ Note that you must perform :code:`import lux` before you load in or create the d
 
 What if my data is stored in a relational database?
 """"""""""""""""""""""""""""""""""""""""""""""""""""""""
-  Lux has `some limited support <https://lux-api.readthedocs.io/en/latest/source/advanced/executor.html#sql-executor>`__ for SQL (currently only tested for Postgres). We are actively working on extending Lux to databases. If you are interested in using this feature, please `contact us <http://lux-project.slack.com/>`_ for more information.
+  Lux has `some limited support <https://lux-api.readthedocs.io/en/latest/source/advanced/executor.html#sql-executor>`__ for SQL (currently only tested for Postgres). We are actively working on extending Lux to databases. If you are interested in using this feature, please `contact us <https://communityinviter.com/apps/lux-project/lux>`_ for more information.
 
 What do I do with date-related attributes in my dataset?
 """"""""""""""""""""""""""""""""""""""""""""""""""""""""
@@ -153,7 +153,7 @@ I'm not able to export my visualizations via the :code:`exported` property.
 
 I have an issue that is not addressed by any of the FAQs.
 """"""""""""""""""""""""""""""""""""""""""""""""""""""""""
-Please submit a `Github Issue <https://github.com/lux-org/lux/issues>`__ or ask a question on `Slack <http://lux-project.slack.com/>`__.
+Please submit a `Github Issue <https://github.com/lux-org/lux/issues>`__ or ask a question on `Slack <https://communityinviter.com/apps/lux-project/lux>`__.
 
 .. Not Currently Supported
 .. - What do I do if I want to change the data type of an attribute?