package fails to install correctly the package dj-database-url helps django communicate with the database heroku usesdj-static and static help django manage static files correctlyand gunicorn is server capable of serving apps in live environment (static files contain style rules and javascript files note some of the required packages may not install on windowsso don' be concerned if you get an error message when you try to install some of them what matters is getting heroku to install the packages on the live deploymentand we'll do that in the next section creating packages list with requirements txt file heroku needs to know which packages our project depends onso we'll use pip to generate file listing them againfrom an active virtual environmentissue the following command(ll_env)learning_logpip freeze requirements txt the freeze command tells pip to write the names of all the packages currently installed in the project into the file requirements txt open requirements txt to see the packages and version numbers installed in your project (windows users might not see all of these lines)requirements txt django=dj-database-url=dj-static=django-bootstrap =gunicorn=static =learning log already depends on six different packages with specific version numbersso it requires specific environment to run properly when we deploy learning logheroku will install all the packages listed in requirements txtcreating an environment with the same packages we're using locally for this reasonwe can be confident the deployed project will behave the same as it does on our local system this is huge advantage as you start to build and maintain various projects on your system nextwe need to add psycopg which helps heroku manage the live databaseto the list of packages open requirements txt and add the line psycopg >this will install version of psycopg or newer version if it' availablerequirements txt django=dj-database-url=dj-static=django-bootstrap =gunicorn=styling and deploying an app